Implement Sprint 1 stories: collections, RBAC, audit logging, load testing

Complete 6 Sprint 1 stories for Epic 1 web migration infrastructure.

Portfolio Collection:
- Add 7 fields: title, slug, url, image, description, websiteType, tags
- Configure R2 storage and authenticated access control

Categories Collection:
- Add nameEn, order, textColor, backgroundColor fields
- Add color picker UI configuration

Posts Collection:
- Add excerpt with 200 char limit and ogImage for social sharing
- Add showInFooter checkbox and status select (draft/review/published)

Role-Based Access Control:
- Add role field to Users collection (admin/editor)
- Create adminOnly and authenticated access functions
- Apply access rules to Portfolio, Categories, Posts, Users collections

Audit Logging System (NFR9):
- Create Audit collection with timestamps for 90-day retention
- Add auditLogger utility for login/logout/content change tracking
- Add auditChange and auditGlobalChange hooks to all collections and globals
- Add cleanupAuditLogs job with 90-day retention policy

Load Testing Framework (NFR4):
- Add k6 load testing with 3 scripts: public-browsing, admin-operations, api-performance
- Configure targets: p95 < 500ms, error rate < 1%, 100 concurrent users
- Add verification script and comprehensive documentation

Other Changes:
- Remove unused Form blocks
- Add Header/Footer audit hooks
- Regenerate Payload TypeScript types

apps/backend/tests/k6/.env.example

@@ -0,0 +1,21 @@
+# K6 Load Testing Environment Variables
+# Copy this file to .env.k6 and customize for your environment
+
+# Target Server Configuration
+BASE_URL=http://localhost:3000
+
+# Admin Credentials (for admin-operations.js)
+ADMIN_EMAIL=admin@enchun.tw
+ADMIN_PASSWORD=your-secure-password-here
+
+# Optional: Override default load profile
+# STAGED_USERS=100
+# STAGED_DURATION=10m
+
+# Optional: Staging environment
+# BASE_URL=https://staging.enchun.tw
+# ADMIN_EMAIL=admin@staging.enchun.tw
+
+# Optional: Production environment (use with caution!)
+# BASE_URL=https://www.enchun.tw
+# ADMIN_EMAIL=admin@enchun.tw