Add 6 new E2E tests for OIDC flow and session persistence

New auth.spec.ts tests:
- OIDC button shows provider name when configured
- OIDC button shows loading state during authentication
- OIDC button is disabled when rate limited
- Session persists after page refresh
- Session persists when navigating between pages
- Logout clears session and redirects to login

E2E test count: 180 → 186 (auth.spec.ts: 14 → 20)
Total tests: 1194 → 1200

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

IMPLEMENTATION_PLAN.md

@@ -4,7 +4,7 @@ This file is maintained by Ralph. Run `./ralph-sandbox.sh plan 3` to generate ta
 
 ## Current Status: Feature Complete
 
-**Test Coverage:** 1014 unit tests (51 files) + 180 E2E tests (12 files) = 1194 total tests
+**Test Coverage:** 1014 unit tests (51 files) + 186 E2E tests (12 files) = 1200 total tests
 
 All P0-P5 items are complete. The project is feature complete.
 
@@ -97,11 +97,11 @@ All P0-P5 items are complete. The project is feature complete.
 | PeriodDateModal | 22 | Period input modal |
 | Skeletons | 29 | Loading states with shimmer |
 
-### E2E Tests (12 files, 180 tests)
+### E2E Tests (12 files, 186 tests)
 | File | Tests | Coverage |
 |------|-------|----------|
 | smoke.spec.ts | 3 | Basic app functionality |
-| auth.spec.ts | 14 | Login, protected routes |
+| auth.spec.ts | 20 | Login, protected routes, OIDC flow, session persistence |
 | dashboard.spec.ts | 40 | Dashboard display, overrides, accessibility |
 | settings.spec.ts | 26 | Settings form, validation, persistence |
 | garmin.spec.ts | 12 | Garmin connection, expiry warnings |
@@ -129,7 +129,6 @@ These are optional enhancements to improve E2E coverage. Not required for featur
 ### Existing File Extensions
 | File | Additional Tests | Focus Area |
 |------|------------------|------------|
-| auth.spec.ts | +6 | OIDC flow, session persistence |
 | calendar.spec.ts | +4 | Responsive behavior, accessibility |
 | settings.spec.ts | +1 | Error recovery on failed save |
 | garmin.spec.ts | +4 | Token refresh, network error recovery |
@@ -149,6 +148,7 @@ These are optional enhancements to improve E2E coverage. Not required for featur
 
 ## Revision History
 
+- 2026-01-13: Added 6 auth E2E tests (OIDC button display, loading states, session persistence across pages/refresh)
 - 2026-01-13: Added 5 settings persistence E2E tests (notification time, timezone, multi-field persistence)
 - 2026-01-13: Added 5 period-logging E2E tests (modal flow, future date restriction, edit/delete flows)
 - 2026-01-13: Added 5 Garmin E2E tests (expiry warnings, expired state, persistence, reconnection)