feat: implement custom fields, gantt view, calendar view, and file encryption

- Custom Fields (FEAT-001):
  - CustomField and TaskCustomValue models with formula support
  - CRUD API for custom field management
  - Formula engine for calculated fields
  - Frontend: CustomFieldEditor, CustomFieldInput, ProjectSettings page
  - Task list API now includes custom_values
  - KanbanBoard displays custom field values

- Gantt View (FEAT-003):
  - TaskDependency model with FS/SS/FF/SF dependency types
  - Dependency CRUD API with cycle detection
  - start_date field added to tasks
  - GanttChart component with Frappe Gantt integration
  - Dependency type selector in UI

- Calendar View (FEAT-004):
  - CalendarView component with FullCalendar integration
  - Date range filtering API for tasks
  - Drag-and-drop date updates
  - View mode switching in Tasks page

- File Encryption (FEAT-010):
  - AES-256-GCM encryption service
  - EncryptionKey model with key rotation support
  - Admin API for key management
  - Encrypted upload/download for confidential projects

- Migrations: 011 (custom fields), 012 (encryption keys), 013 (task dependencies)
- Updated issues.md with completion status

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

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

frontend/src/components/KanbanBoard.tsx

@@ -1,7 +1,9 @@
 import { useState } from 'react'
+import { CustomValueResponse } from '../services/customFields'
 
 interface Task {
   id: string
+  project_id: string
   title: string
   description: string | null
   priority: string
@@ -11,8 +13,10 @@ interface Task {
   assignee_id: string | null
   assignee_name: string | null
   due_date: string | null
+  start_date: string | null
   time_estimate: number | null
   subtask_count: number
+  custom_values?: CustomValueResponse[]
 }
 
 interface TaskStatus {
@@ -133,6 +137,12 @@ export function KanbanBoard({
         {task.subtask_count > 0 && (
           <span style={styles.subtaskBadge}>{task.subtask_count} subtasks</span>
         )}
+        {/* Display custom field values (limit to first 2 for compact display) */}
+        {task.custom_values?.slice(0, 2).map((cv) => (
+          <span key={cv.field_id} style={styles.customValueBadge}>
+            {cv.field_name}: {cv.display_value || cv.value || '-'}
+          </span>
+        ))}
       </div>
     </div>
   )
@@ -280,6 +290,17 @@ const styles: Record<string, React.CSSProperties> = {
   subtaskBadge: {
     color: '#999',
   },
+  customValueBadge: {
+    backgroundColor: '#f3e5f5',
+    color: '#7b1fa2',
+    padding: '2px 6px',
+    borderRadius: '4px',
+    fontSize: '10px',
+    maxWidth: '100px',
+    overflow: 'hidden',
+    textOverflow: 'ellipsis',
+    whiteSpace: 'nowrap',
+  },
   emptyColumn: {
     textAlign: 'center',
     padding: '24px',