Complete ADR-008 Phase 1: API Versioning Strategy

Implement URI-based API versioning with /api/v1 prefix across all routes.
This establishes a foundation for future API evolution and breaking changes.

Changes:
- server.ts: All routes mounted under /api/v1/ (15 route handlers)
- apiClient.ts: Base URL updated to /api/v1
- swagger.ts: OpenAPI server URL changed to /api/v1
- Redirect middleware: Added backwards compatibility for /api/* → /api/v1/*
- Tests: Updated 72 test files with versioned path assertions
- ADR documentation: Marked Phase 1 as complete (Accepted status)

Test fixes:
- apiClient.test.ts: 27 tests updated for /api/v1 paths
- user.routes.ts: 36 log messages updated to reflect versioned paths
- swagger.test.ts: 1 test updated for new server URL
- All integration/E2E tests updated for versioned endpoints

All Phase 1 acceptance criteria met:
✓ Routes use /api/v1/ prefix
✓ Frontend requests /api/v1/
✓ OpenAPI docs reflect /api/v1/
✓ Backwards compatibility via redirect middleware
✓ Tests pass with versioned paths

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

docs/adr/index.md

@@ -20,7 +20,7 @@ This directory contains a log of the architectural decisions made for the Flyer
 ## 3. API & Integration
 
 **[ADR-003](./0003-standardized-input-validation-using-middleware.md)**: Standardized Input Validation using Middleware (Accepted)
-**[ADR-008](./0008-api-versioning-strategy.md)**: API Versioning Strategy (Proposed)
+**[ADR-008](./0008-api-versioning-strategy.md)**: API Versioning Strategy (Accepted - Phase 1 Complete)
 **[ADR-018](./0018-api-documentation-strategy.md)**: API Documentation Strategy (Accepted)
 **[ADR-022](./0022-real-time-notification-system.md)**: Real-time Notification System (Proposed)
 **[ADR-028](./0028-api-response-standardization.md)**: API Response Standardization and Envelope Pattern (Implemented)