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/TaskDetailModal.tsx

@@ -4,9 +4,12 @@ import { Comments } from './Comments'
 import { TaskAttachments } from './TaskAttachments'
 import { UserSelect } from './UserSelect'
 import { UserSearchResult } from '../services/collaboration'
+import { customFieldsApi, CustomField, CustomValueResponse } from '../services/customFields'
+import { CustomFieldInput } from './CustomFieldInput'
 
 interface Task {
   id: string
+  project_id: string
   title: string
   description: string | null
   priority: string
@@ -18,6 +21,7 @@ interface Task {
   due_date: string | null
   time_estimate: number | null
   subtask_count: number
+  custom_values?: CustomValueResponse[]
 }
 
 interface TaskStatus {
@@ -59,6 +63,44 @@ export function TaskDetailModal({
       : null
   )
 
+  // Custom fields state
+  const [customFields, setCustomFields] = useState<CustomField[]>([])
+  const [customValues, setCustomValues] = useState<CustomValueResponse[]>([])
+  const [editCustomValues, setEditCustomValues] = useState<Record<string, string | number | null>>({})
+  const [loadingCustomFields, setLoadingCustomFields] = useState(false)
+
+  // Load custom fields for the project
+  useEffect(() => {
+    if (task.project_id) {
+      loadCustomFields()
+    }
+  }, [task.project_id])
+
+  const loadCustomFields = async () => {
+    setLoadingCustomFields(true)
+    try {
+      const response = await customFieldsApi.getCustomFields(task.project_id)
+      setCustomFields(response.fields)
+    } catch (err) {
+      console.error('Failed to load custom fields:', err)
+    } finally {
+      setLoadingCustomFields(false)
+    }
+  }
+
+  // Initialize custom values from task
+  useEffect(() => {
+    setCustomValues(task.custom_values || [])
+    // Build edit values map
+    const valuesMap: Record<string, string | number | null> = {}
+    if (task.custom_values) {
+      task.custom_values.forEach((cv) => {
+        valuesMap[cv.field_id] = cv.value
+      })
+    }
+    setEditCustomValues(valuesMap)
+  }, [task.custom_values])
+
   // Reset form when task changes
   useEffect(() => {
     setEditForm({
@@ -108,6 +150,21 @@ export function TaskDetailModal({
         payload.time_estimate = null
       }
 
+      // Include custom field values (only non-formula fields)
+      const customValuesPayload = Object.entries(editCustomValues)
+        .filter(([fieldId]) => {
+          const field = customFields.find((f) => f.id === fieldId)
+          return field && field.field_type !== 'formula'
+        })
+        .map(([fieldId, value]) => ({
+          field_id: fieldId,
+          value: value,
+        }))
+
+      if (customValuesPayload.length > 0) {
+        payload.custom_values = customValuesPayload
+      }
+
       await api.patch(`/tasks/${task.id}`, payload)
       setIsEditing(false)
       onUpdate()
@@ -118,6 +175,13 @@ export function TaskDetailModal({
     }
   }
 
+  const handleCustomFieldChange = (fieldId: string, value: string | number | null) => {
+    setEditCustomValues((prev) => ({
+      ...prev,
+      [fieldId]: value,
+    }))
+  }
+
   const handleAssigneeChange = (userId: string | null, user: UserSearchResult | null) => {
     setEditForm({ ...editForm, assignee_id: userId || '' })
     setSelectedAssignee(user)
@@ -349,6 +413,50 @@ export function TaskDetailModal({
                 <div style={styles.subtaskInfo}>{task.subtask_count} subtask(s)</div>
               </div>
             )}
+
+            {/* Custom Fields Section */}
+            {customFields.length > 0 && (
+              <>
+                <div style={styles.customFieldsDivider} />
+                <div style={styles.customFieldsHeader}>Custom Fields</div>
+                {loadingCustomFields ? (
+                  <div style={styles.loadingText}>Loading...</div>
+                ) : (
+                  customFields.map((field) => {
+                    // Get the value for this field
+                    const valueResponse = customValues.find(
+                      (v) => v.field_id === field.id
+                    ) || {
+                      field_id: field.id,
+                      field_name: field.name,
+                      field_type: field.field_type,
+                      value: editCustomValues[field.id] ?? null,
+                      display_value: null,
+                    }
+
+                    // For editing mode, create a modified value response with edit values
+                    const displayValue = isEditing
+                      ? {
+                          ...valueResponse,
+                          value: editCustomValues[field.id] ?? valueResponse.value,
+                        }
+                      : valueResponse
+
+                    return (
+                      <div key={field.id} style={styles.sidebarField}>
+                        <CustomFieldInput
+                          field={field}
+                          value={displayValue}
+                          onChange={handleCustomFieldChange}
+                          disabled={!isEditing || field.field_type === 'formula'}
+                          showLabel={true}
+                        />
+                      </div>
+                    )
+                  })
+                )}
+              </>
+            )}
           </div>
         </div>
       </div>
@@ -571,6 +679,23 @@ const styles: Record<string, React.CSSProperties> = {
     fontSize: '14px',
     boxSizing: 'border-box',
   },
+  customFieldsDivider: {
+    height: '1px',
+    backgroundColor: '#ddd',
+    margin: '20px 0',
+  },
+  customFieldsHeader: {
+    fontSize: '12px',
+    fontWeight: 600,
+    color: '#666',
+    marginBottom: '16px',
+    textTransform: 'uppercase',
+  },
+  loadingText: {
+    fontSize: '13px',
+    color: '#888',
+    fontStyle: 'italic',
+  },
 }
 
 export default TaskDetailModal