v1.6.0 CI hardening: dual-bridge integration, UI tests, lint, coverage, widget+iPad build

[tashda]

Why

The v1.6.0 multi-bridge release significantly enlarges the test surface — concurrent BridgeRegistry sessions, merged-mode aggregation, per-bridge UI, typed bridge-aware navigation — and our CI is not currently exercising it adequately:

• Multi-bridge integration coverage: Full CI starts a single mock bridge on localhost:8080. The dual-bridge docker stack added in Multi-bridge Phase 1.6: Test-center extension for dual-bridge fixtures #67 (localhost:8082, seeder-2) is unused by CI; cross-bridge correctness is verified only by unit tests with mocked sessions.
• UI tests dormant: 9 UI test files (Connection, Devices, Groups, Home, Logs, Settings) run nowhere because of a redesign-era pause. Multi-bridge introduces switcher, Saved Bridges, bridge picker, attribution badges, per-bridge Settings — none of it is exercised by CI.
• ConnectionHistoryTests skipped on Fast CI: substrate the SavedBridges promotion (Multi-bridge Phase 1.1: Promote ConnectionHistory into SavedBridges model #62) sits on; gate doesn't verify our headline model.
• No iPad build: merged-mode UI may break on iPad split layouts; Multi-bridge Phase 2.9: Polish — filter chips, color picker, iPad, perf #77 carries area:ipad.
• No CLAUDE.md mechanical enforcement: "No Stepper", "no trailing ellipsis", "use DesignTokens" have zero CI teeth.
• No widget-target verification: a new file importing AppEnvironment that wasn't added to widget membershipExceptions only fails at actual widget compile.
• No coverage signal: both plans set codeCoverage: false.

What

Pri	Task	Where
P0	Dual-bridge mock startup script + MultiBridgeIntegrationTests exercising BridgeRegistry against both	Full CI
P0	Re-enable UI tests in Full CI	Full CI
P1	Fix ConnectionHistoryTests isolation; remove from skip list	Fast CI
P1	Add iPad simulator build (build-only, no tests)	Full CI
P2	grep-based lint (Stepper, …/... in UI strings)	Fast CI
P2	Build widget target explicitly	Fast CI
P3	Emit coverage % in Fast CI step summary	Fast CI
P3	Address remaining concurrency-skip tests (HomeLayoutStoreTests, NotificationPreferencesTests)	both

Out of scope (tracked separately): Keychain abstraction for the two ConnectionConfigTests/testSaveAndLoad* skips and the related Z2MIntegrationTests/testReloadedPersistedConfigConnectsAndReceivesBridgeInfo skip — that needs a Keychain protocol + in-memory test double, multi-day refactor.

[tashda]

Landed. Both CI lanes green on dev tip 82f2272:

• Fast CI ✅ — lint, widget build, unit tests with coverage in step summary
• Full CI
  • Gate ✅
  • Unit + Integration Tests ✅ — dual mock bridges, MultiBridgeIntegrationTests covers cross-bridge isolation
  • iPad build (build-only) ✅
  • UI Tests (smoke) — gated behind run-ui-tests PR label

What landed:

• Dual mock-bridge support in start-mock-bridge.sh (MULTI_BRIDGE=1)
• New MultiBridgeIntegrationTests exercising BridgeRegistry against both real WebSocket peers
• iPad build-only job in Full CI
• CLAUDE.md grep lint (Stepper, trailing ellipsis) in Fast CI
• Explicit widget-target build in Fast CI
• Coverage % in Fast CI step summary
• New MultiBridgeTestCase base class drains BridgeRegistry sessions in tearDown to fix the malloc-free crash that previously skipped BridgeRegistryTests
• Fixed Z2MWebSocketSessionDelegate.awaitOpen continuation double-resume

Open follow-ups (not blocking v1.6.0):

• UI Tests need investigation before they can run unconditionally — they hung 20 min with zero test execution on first re-enable. Unblocked by labeling a PR run-ui-tests once green.
• ConnectionHistoryTests, HomeLayoutStoreTests, NotificationPreferencesTests skipped on CI — Keychain abstraction + Xcode 26.3 isolation work.
• Test flake: Z2MIntegrationTests/testReceivesAllSeededDeviceCategories occasionally trips the 10s WebSocket connect timeout on slow runner moments. Bumping websocketConnectionTimeout would help; tracked here.