test(webapp): update the theme preference tests for the new theme set

The test's VALID_THEMES still listed "classic", which this branch removed
from the enum, so both loops asserted a value the schema now rejects.
Swapped in the current set and pinned the migration behaviour the removal
implies: a stored "classic" normalizes to dark and parses to undefined.

These are excluded from tsconfig.check.json, so the stale annotation
never surfaced in typecheck.

Author: samejr

apps/webapp/test/themePreference.test.ts

@@ -2,7 +2,7 @@ import { describe, expect, it } from "vitest";
 import { parseDashboardPreferences } from "~/utils/dashboardPreferences";
 import { normalizeThemePreference, type ThemePreference } from "~/utils/themePreference";
 
-const VALID_THEMES: ThemePreference[] = ["classic", "system", "dark", "light"];
+const VALID_THEMES: ThemePreference[] = ["system", "dark", "light", "black", "white"];
 
 describe("normalizeThemePreference", () => {
   it("returns each valid value unchanged", () => {
@@ -12,6 +12,9 @@ describe("normalizeThemePreference", () => {
   });
 
   it("falls back to dark for legacy/unknown values", () => {
+    // Classic is retired. Anyone still holding it lands on Dark, which at
+    // contrast 0 renders the palette Classic used to ship.
+    expect(normalizeThemePreference("classic")).toBe("dark");
     expect(normalizeThemePreference("solarized")).toBe("dark");
     expect(normalizeThemePreference("")).toBe("dark");
     expect(normalizeThemePreference(42)).toBe("dark");
@@ -24,13 +27,18 @@ describe("normalizeThemePreference", () => {
 });
 
 describe("DashboardPreferences theme schema", () => {
-  it("accepts all four theme values", () => {
+  it("accepts every theme value", () => {
     for (const theme of VALID_THEMES) {
       const result = parseDashboardPreferences({ version: "1", projects: {}, theme });
       expect(result.theme).toBe(theme);
     }
   });
 
+  it("drops a stored classic theme", () => {
+    const result = parseDashboardPreferences({ version: "1", projects: {}, theme: "classic" });
+    expect(result.theme).toBeUndefined();
+  });
+
   it("accepts preferences without a theme", () => {
     const result = parseDashboardPreferences({ version: "1", projects: {} });
     expect(result.theme).toBeUndefined();