fix(ci): unbreak Dart Format and Dart Analyze on main

[hiroshihorie]

Build has been failing on main and therefore on every PR, regardless of what the PR changes — visible on #1180, max/fix-ios-audio-session-before-recording and sync-upstream-2.11.0, all of which show Build ✗ with Changeset Check ✓. Two jobs are responsible.

Dart Format

Three files under scripts/ are not formatted, so dart format . --set-exit-if-changed exits 1. Straight from the CI log:

Formatted scripts/check_version.dart
Formatted scripts/create_change.dart
Formatted scripts/create_version.dart
Formatted 227 files (3 changed) in 0.72 seconds.
##[error]Process completed with exit code 1

Formatting only, no behaviour change.

Dart Analyze

lib/src/token_source/caching.dart:138:9 • unawaited_return_in_try_block
lib/src/token_source/caching.dart:144:7 • unawaited_return_in_try_block

CachingTokenSource.fetch returned resultFuture from inside its try, so the surrounding catch could not observe a failure from that future and finally removed the in-flight entry before it settled. Both returns now await.

Behaviour is unchanged — the completer is completed on the line immediately before each return, so the awaited future is already resolved — but errors now route through the existing catch, and the in-flight map is cleared only once the request settles. AGENTS.md calls out un-awaited async state updates as a recurring bug class here, so this is a real latent issue rather than a lint silence. Includes a patch type="fixed" changeset.

The analysis_options churn, and a coverage hole it was hiding

flutter analyze kept leaving analysis_options.yaml modified. The cause is AnalysisOptionsMigration (flutter_tools/lib/src/migrations/analysis_options_migration.dart, invoked from project.dart:429), which appends seven patterns — build/**, android/**, ios/**, web/**, windows/**, macos/**, linux/** — on every flutter analyze / pub get / run. It is unconditional; there is no feature flag or config to disable it, unlike the UIScene migrator's enable-uiscene-migration.

Committing the patterns makes it a no-op. But one of them matters: this package keeps real Dart source in web/ (the E2EE worker), not just assets, so web/** silently drops it from analysis. That was already happening in CI, since flutter analyze runs the migrator before it analyzes.

Passing the path explicitly does not work — dart analyze web/ still honours the root exclude. I confirmed this by appending a deliberate type error to web/e2ee.logger.dart: it reported No issues found!. Giving web/ its own analysis_options.yaml creates a separate context that is genuinely analyzed; the same canary then correctly reports return_of_invalid_type. That file mirrors the root's error overrides and its formatter settings (page_width: 120, trailing_commas: preserve) so dart format output is unaffected, and build.yaml gains a dart analyze web/ step.

Verified locally

dart format . --set-exit-if-changed   PASS  (227 files, 0 changed)
flutter analyze                        PASS  (No issues found)
dart analyze web/                      PASS  (and fails on an injected error)
flutter test                           PASS  (+398)
dart run scripts/check_version.dart    PASS
import_sorter --exit-if-changed        PASS

Not included

Pinning the Flutter version in .github/actions/setup-flutter/action.yml, which currently passes only channel: stable and so tracks whatever the newest stable release is. That is a genuine fragility — unawaited_return_in_try_block arrived this way — but it is a separate decision from unbreaking CI, and worth its own discussion.

Draft because #1180 should confirm this actually turns Build green once rebased on it.