feat: complete issue fixes and implement remaining features

## Critical Issues (CRIT-001~003) - All Fixed
- JWT secret key validation with pydantic field_validator
- Login audit logging for success/failure attempts
- Frontend API path prefix removal

## High Priority Issues (HIGH-001~008) - All Fixed
- Project soft delete using is_active flag
- Redis session token bytes handling
- Rate limiting with slowapi (5 req/min for login)
- Attachment API permission checks
- Kanban view with drag-and-drop
- Workload heatmap UI (WorkloadPage, WorkloadHeatmap)
- TaskDetailModal integrating Comments/Attachments
- UserSelect component for task assignment

## Medium Priority Issues (MED-001~012) - All Fixed
- MED-001~005: DB commits, N+1 queries, datetime, error format, blocker flag
- MED-006: Project health dashboard (HealthService, ProjectHealthPage)
- MED-007: Capacity update API (PUT /api/users/{id}/capacity)
- MED-008: Schedule triggers (cron parsing, deadline reminders)
- MED-009: Watermark feature (image/PDF watermarking)
- MED-010~012: useEffect deps, DOM operations, PDF export

## New Files
- backend/app/api/health/ - Project health API
- backend/app/services/health_service.py
- backend/app/services/trigger_scheduler.py
- backend/app/services/watermark_service.py
- backend/app/core/rate_limiter.py
- frontend/src/pages/ProjectHealthPage.tsx
- frontend/src/components/ProjectHealthCard.tsx
- frontend/src/components/KanbanBoard.tsx
- frontend/src/components/WorkloadHeatmap.tsx

## Tests
- 113 new tests passing (health: 32, users: 14, triggers: 35, watermark: 32)

## OpenSpec Archives
- add-project-health-dashboard
- add-capacity-update-api
- add-schedule-triggers
- add-watermark-feature
- add-rate-limiting
- enhance-frontend-ux
- add-resource-management-ui

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

frontend/src/components/ResourceHistory.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect } from 'react'
+import { useState, useEffect, useCallback } from 'react'
 import { auditService, AuditLog } from '../services/audit'
 
 interface ResourceHistoryProps {
@@ -12,11 +12,7 @@ export function ResourceHistory({ resourceType, resourceId, title = 'Change Hist
   const [loading, setLoading] = useState(true)
   const [expanded, setExpanded] = useState(false)
 
-  useEffect(() => {
-    loadHistory()
-  }, [resourceType, resourceId])
-
-  const loadHistory = async () => {
+  const loadHistory = useCallback(async () => {
     setLoading(true)
     try {
       const response = await auditService.getResourceHistory(resourceType, resourceId, 10)
@@ -26,7 +22,11 @@ export function ResourceHistory({ resourceType, resourceId, title = 'Change Hist
     } finally {
       setLoading(false)
     }
-  }
+  }, [resourceType, resourceId])
+
+  useEffect(() => {
+    loadHistory()
+  }, [loadHistory])
 
   const formatChanges = (changes: AuditLog['changes']): string => {
     if (!changes || changes.length === 0) return ''