refactor: contest label split by type

.claude/rules/coding-style.md

@@ -49,12 +49,20 @@ Extract to `src/lib/utils/` with adjacent tests.
 
 Ensure guard clauses don't make later code unreachable. If an early return covers all remaining cases, delete the dead code below it rather than leaving it.
 
+## Dispatcher and Handler Domains
+
+A classifier must not match more broadly than its handler accepts (`startsWith` classifier → anchored-regex handler throws on the gap). Fix both sides: tighten the classifier, and return `null` instead of throwing.
+
 ## Dead Code: Three-Condition Rule
 
 Delete function only if: (1) zero callers, (2) replacement exists, (3) dependent fields also deleted.
 
 Before removing an import, grep the entire file for all usages — removing one call site doesn't mean no others exist.
 
+## Barrel Exports
+
+`index.ts` re-exports public API only. Files within the same module import each other directly — never through the barrel (circular dependency).
+
 ## Residual-Reference Sweeps
 
 When removing a dependency or renaming a symbol, sweep the **whole repo**, not just `src`:

.claude/rules/testing.md

@@ -13,11 +13,11 @@ paths:
 
 - **Tests ship with implementation** — same commit; feature not done until tests pass. Never defer tests for non-trivial logic
 - **English only** — describe expected behavior (e.g., `'returns empty array when workbooks is empty'`)
-- **Test integrity** — never weaken assertions to make tests pass; fix implementation instead
+- **Test integrity** — never weaken assertions to make tests pass; fix implementation instead. Never let the expected value be computed by the code under test: `expect(f(x)).toBe(map.get(expected))` where `f` is `map.get(classify(x))`, or a fixture whose `expected` calls a production function. Both pass unconditionally. Expected values are literals
 - **Unused imports** — signal missing tests, not dead code — add the test case first
 - **TDD exceptions** — skip test-first for exploratory spikes, type-only changes, and config files with no branching logic
 - **Component testing** — extract logic to `utils/`; omit component Vitest if template-only **and** E2E covers rendering paths
-- **Coverage** — cover happy path, error cases, and domain edge cases (empty arrays, null, enum extremes). Treat low coverage as a signal to review, not a target
+- **Coverage** — cover happy path, error cases, and domain edge cases of the input values (empty arrays, null, enum extremes); for registry coverage see Assertions & Structure. Treat low coverage as a signal to review, not a target
 
 ## File Layout & Environment
 
@@ -40,6 +40,8 @@ paths:
 - `Promise<void>`: use `await fn()` to assert no throw, or `.resolves.toBeUndefined()`. **Never** bare `.resolves` (false-positive)
 - **Stubs**: parameter types must match production signature — use domain types (`TaskGrade`), not `string`
 - **Test data**: realistic values (real task IDs, grade names). Extract shared fixtures to file/describe scope; inline for single-use
+- **Registry exhaustiveness**: `Record<string, T>` and `new Map([...])` give no compile-time enum coverage — assert it at runtime, with a named, commented exception list so deliberate gaps stay documented: `expect(Object.values(Enum).filter((key) => !REGISTRY.has(key))).toEqual(KNOWN_GAPS)` (`Record` registries: swap `REGISTRY.has(key)` for the `Object.hasOwn` form above)
+- **Test count as a proxy**: after a file split, compare counts (`--reporter=verbose`) — a drop means a describe block was lost in the move. A deliberate drop is valid only when mutation analysis shows detection is unchanged; record the evidence in the commit
 
 Group by scenario, not flat:
 

.claude/skills/add-contest-table-provider/instructions.md

@@ -41,14 +41,18 @@ Step 0 (seed check) is already done. Confirm the following before touching code:
 ### Tests first
 
 - [ ] Add exports to `src/lib/contests/fixtures/contest_type.ts` and `contest_name_labels.ts`
-- [ ] Add 3 `describe` blocks to `src/lib/contests/utils/contest.test.ts`: classify / priority / name label
-- [ ] `pnpm test:unit src/lib/contests/utils/contest.test.ts` — **RED**
+- [ ] Add `describe` block to `src/lib/contests/utils/classification.test.ts` (classify)
+- [ ] Add `describe` block to `src/lib/contests/utils/priority.test.ts` (priority)
+- [ ] Add `describe` block to `src/lib/contests/utils/labels/index.test.ts` (name label)
+- [ ] `pnpm test:unit src/lib/contests/` — **RED**
 
 ### Implement
 
-- [ ] Add branches to `classifyContest` / `contestTypePriorities` / `getContestNameLabel`
+- [ ] `CONTEST_TYPES_BY_ID` or `CLASSIFICATION_RULES` in `src/lib/contests/utils/classification.ts`
+- [ ] `contestTypePriorities` in `src/lib/contests/utils/priority.ts`
   - After priority insertion, all later entries shift +1 → **update JSDoc numeric ranges** (4 category names are immutable)
   - Fix hardcoded priority-diff expected values in `src/test/lib/utils/task.test.ts` (-1 per shifted entry)
+- [ ] `LABEL_GENERATORS` in `src/lib/contests/utils/labels/index.ts` (add label generator, create per-type file if complex)
 - [ ] **GREEN**
 
 ---

.claude/skills/verify-test-strength/SKILL.md

@@ -0,0 +1,11 @@
+---
+name: verify-test-strength
+description: Prove what a test file actually detects by mutating the production source. Use when a test file's value is in doubt — after writing tests for existing behavior, before deleting or compressing tests, or when reviewing a large test file that may be tautological.
+argument-hint: '[test-file-path]'
+---
+
+Measure the detection power of the tests for: $ARGUMENTS
+
+1. **Baseline** — run the target test file; record the pass count
+2. **Mutate** — apply the mutants in [instructions.md](instructions.md) one at a time, restoring after each; record which test names fail
+3. **Report** — a mutant × detecting-test matrix; name the missing tests and the deletion candidates

.claude/skills/verify-test-strength/instructions.md

@@ -0,0 +1,39 @@
+# Mutation-Based Test Verification
+
+Mutate the production source, never the test. A test's worth is what it detects, not how many cases it enumerates.
+
+## Mutants
+
+Apply 3–4, one at a time, restoring before the next.
+
+| Mutant                               | Detects                               |
+| ------------------------------------ | ------------------------------------- |
+| Remove one entry from a lookup table | Registry exhaustiveness               |
+| Swap two values that encode an order | The ordering contract                 |
+| Make the function return a constant  | That the function is exercised at all |
+| Invert one guard clause              | Boundary handling                     |
+
+**Mutants must preserve the original type.** A `0.5` mutant for an integer field is caught by a type check (`Number.isInteger`), not by the assertion being measured — a false positive about the test's strength.
+
+## Procedure
+
+```bash
+cp <source> /tmp/source.bak                      # 1. save
+perl -0777 -pi -e 's/<pattern>/<mutant>/' <source>  # 2. mutate
+pnpm exec vitest run <test-file> --reporter=verbose  # 3. run
+cp /tmp/source.bak <source> && git diff <source>     # 4. restore, then verify
+```
+
+Repeat per mutant. Step 4 is not optional — an unrestored mutant silently poisons every later measurement.
+
+## Reading results
+
+Read stdout from `--reporter=default` / `--reporter=verbose`. **Never read a cached JSON report** (`.vitest/json/output.json`) — under a CLI wrapper it may not be rewritten, leaving a stale file from a previous run that reports the mutant as undetected.
+
+## Interpreting
+
+- **A mutant nothing catches** — a missing test. Write it.
+- **A test catching nothing that other tests miss** — a deletion candidate. Confirm by re-running the full mutant set without it.
+- **N tests failing on one mutant** — not N times the value. Parameterized cases over one fixture usually report the same fact N times; the count is a proxy, not evidence.
+
+Record the matrix in the commit message or `plan.md` when it justifies removing tests — it is the evidence `.claude/rules/testing.md` requires for a deliberate test-count drop.

docs/guides/architecture.md

@@ -158,7 +158,12 @@ src/lib/
 ├── clients/        # 外部 API クライアント（AtCoder Problems, AOJ）
 ├── components/     # 共通 UI コンポーネント（GradeLabel, TaskGradeList, TaskList, FormWrapper 等）
 ├── constants/      # アプリ定数
-├── contests/       # コンテスト分類・ラベル生成・優先度（types/, utils/, fixtures/）
+├── contests/       # コンテスト分類・ラベル生成・優先度
+│   ├── types/      # ContestType, ContestPrefix 等の型定義
+│   ├── utils/      # classification, priority, task_index_label
+│   │   ├── labels/ # 種別ごとのラベル生成（axc, joi, past, aoj, ...）
+│   │   └── prefixes.ts # 定数辞書（ABC_LIKE, AOJ_COURSES 等）
+│   └── fixtures/   # テストデータ
 ├── server/         # サーバー専用の共有インフラ
 │   ├── database.ts # Prisma クライアント（14+ サービスが依存）
 │   ├── tasks/      # cache.ts など複数 feature 共有のサーバ処理

docs/guides/how-to-add-contest-table-provider.md

@@ -7,7 +7,7 @@
 ## 事前確認
 
 - [ ] `ContestType`（`src/lib/contests/types/contest.ts`）— 既存で対応できるか？複数 contest_id を統一表示するなら複合型
-- [ ] `classifyContest()`（`src/lib/contests/utils/contest.ts`）— 新 contest_id に正しい ContestType を返すか
+- [ ] `classifyContest()`（`src/lib/contests/utils/classification.ts`）— 新 contest_id に正しい ContestType を返すか
 - [ ] `prisma/tasks.ts` にデータが存在するか（複合型は `prisma/contest_task_pairs.ts` も）
 - [ ] 実装パターン判定（後述4パターン）
 - [ ] JOI: 2026 年より `joi{YYYY}ho` → `joi{YYYY}sf`。regex は `(ho|sf)` 対応済み

prisma/seed.ts

@@ -24,7 +24,7 @@ import { hashPassword } from '../src/features/auth/server/password';
 import { getTaskGrade } from '../src/lib/types/task';
 import type { PlacementCreate } from '../src/features/workbooks/types/workbook_placement';
 
-import { classifyContest } from '../src/lib/contests/utils/contest';
+import { classifyContest } from '../src/lib/contests/utils/classification';
 
 import { users, USER_PASSWORD_FOR_SEED } from './users';
 import { tasks } from './tasks';

src/features/tasks/utils/contest-table/abc_providers.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/abs_provider.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/acl_providers.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/agc_provider.ts

@@ -1,7 +1,7 @@
 import { type ContestTableMetaData } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/arc_providers.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/awc_provider.ts

@@ -5,7 +5,7 @@ import {
 import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests';
 
 import { ContestTableProviderBase, parseContestRound } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/axc_like_provider.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/dp_providers.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/fps24_provider.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/joi_providers.test.ts

@@ -81,7 +81,7 @@ describe('JOIFirstQualRoundProvider', () => {
   test('expects to handle invalid contest IDs gracefully', () => {
     const provider = new JOIFirstQualRoundProvider(ContestType.JOI);
 
-    expect(provider.getContestRoundLabel('invalid-id')).toBe('INVALID-ID'); // See: getContestNameLabel() in src/lib/contests/utils/contest.ts
+    expect(provider.getContestRoundLabel('invalid-id')).toBe('INVALID-ID'); // See: getContestNameLabel() in src/lib/contests/
     expect(provider.getContestRoundLabel('joi2024yo1d')).toBe('2024d'); // 'd' doesn't match valid round (a|b|c)
   });
 

src/features/tasks/utils/contest-table/joi_providers.ts

@@ -7,7 +7,7 @@ import {
 import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest, getContestNameLabel } from '$lib/contests/utils/contest';
+import { classifyContest, getContestNameLabel } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/math_and_algorithm_provider.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/tessoku_book_providers.ts

@@ -6,7 +6,7 @@ import {
 import { ContestType } from '$lib/contests/types/contest';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/tasks/utils/contest-table/typical90_provider.ts

@@ -4,7 +4,7 @@ import {
 } from '$features/tasks/types/contest-table/contest_table_provider';
 import type { TaskResult } from '$lib/types/task';
 
-import { classifyContest } from '$lib/contests/utils/contest';
+import { classifyContest } from '$lib/contests';
 
 import { ContestTableProviderBase } from './contest_table_provider_base';
 

src/features/workbooks/components/detail/WorkBookTasksTable.svelte

@@ -14,7 +14,7 @@
   import GradeLabel from '$lib/components/GradeLabel.svelte';
   import ExternalLinkWrapper from '$lib/components/ExternalLinkWrapper.svelte';
 
-  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests';
   import { getTaskUrl, removeTaskIndexFromTitle } from '$lib/utils/task';
 
   import type {

src/lib/components/SubmissionStatus/UpdatingModal.svelte

@@ -8,7 +8,7 @@
   import { submission_statuses } from '$lib/services/submission_status';
   import { errorMessageStore } from '$lib/stores/error_message';
 
-  import { getContestNameLabel } from '$lib/contests/utils/contest';
+  import { getContestNameLabel } from '$lib/contests';
   import InputFieldWrapper from '$lib/components/InputFieldWrapper.svelte';
 
   interface Props {

src/lib/components/TagForm.svelte

@@ -14,7 +14,7 @@
   import type { Task } from '$lib/types/task';
   import type { Tag } from '$lib/types/tag';
 
-  import { getContestNameLabel } from '$lib/contests/utils/contest';
+  import { getContestNameLabel } from '$lib/contests';
   import { ATCODER_BASE_CONTEST_URL } from '$lib/constants/urls';
 
   interface Props {

src/lib/components/TaskForm.svelte

@@ -10,7 +10,7 @@
     Label,
     Button,
   } from 'flowbite-svelte';
-  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests';
   import { taskGradeValues, type Task } from '$lib/types/task';
   import { getTaskGradeLabel, removeTaskIndexFromTitle } from '$lib/utils/task';
 

src/lib/components/TaskList.svelte

@@ -21,7 +21,7 @@
 
   import { getBackgroundColorFrom } from '$lib/services/submission_status';
 
-  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests';
   import {
     countAcceptedTasks,
     countAllTasks,

src/lib/components/TaskListSorted.svelte

@@ -12,7 +12,7 @@
   } from 'flowbite-svelte';
   import type { TaskResults } from '$lib/types/task';
 
-  import { addContestNameToTaskIndex } from '$lib/contests/utils/contest';
+  import { addContestNameToTaskIndex } from '$lib/contests';
   import { removeTaskIndexFromTitle } from '$lib/utils/task';
 
   interface Props {

src/lib/contests/fixtures/contest_name_and_task_index.ts

@@ -6,7 +6,7 @@ import {
   getAojContestLabel,
   PAST_TRANSLATIONS,
   AOJ_COURSES,
-} from '$lib/contests/utils/contest';
+} from '$lib/contests';
 
 export type TestCaseForContestNameAndTaskIndex = {
   contestId: string;

src/lib/contests/fixtures/contest_name_labels.ts

@@ -139,6 +139,60 @@ export const fps24 = [
   }),
 ];
 
+export const aojCourses = [
+  createTestCaseForContestNameLabel('AOJ, ITP1')({
+    contestId: 'ITP1',
+    expected: '（プログラミング入門）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, ALDS1')({
+    contestId: 'ALDS1',
+    expected: '（アルゴリズムとデータ構造入門）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, ITP2')({
+    contestId: 'ITP2',
+    expected: '（プログラミング応用）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, DPL')({
+    contestId: 'DPL',
+    expected: '（組み合わせ最適化）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, GRL')({
+    contestId: 'GRL',
+    expected: '（グラフ）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, DSL')({
+    contestId: 'DSL',
+    expected: '（データ構造）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, CGL')({
+    contestId: 'CGL',
+    expected: '（計算幾何学）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, NTL')({
+    contestId: 'NTL',
+    expected: '（整数論）',
+  }),
+];
+
+export const aojPck = [
+  createTestCaseForContestNameLabel('AOJ, PCK Prelim 2024')({
+    contestId: 'PCKPrelim2024',
+    expected: '（パソコン甲子園 予選 2024）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, PCK Final 2023')({
+    contestId: 'PCKFinal2023',
+    expected: '（パソコン甲子園 本選 2023）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, PCK Prelim 2005')({
+    contestId: 'PCKPrelim2005',
+    expected: '（パソコン甲子園 予選 2005）',
+  }),
+  createTestCaseForContestNameLabel('AOJ, PCK Final 2004')({
+    contestId: 'PCKFinal2004',
+    expected: '（パソコン甲子園 本選 2004）',
+  }),
+];
+
 export const aojJag = [
   createTestCaseForContestNameLabel('AOJ, JAG Prelim 2016 A')({
     contestId: 'JAGPrelim2016A',