feat(CF-301): Implement task_move_project function

Added task_move_project tool to move tasks between projects while
preserving all relationships and history:

Changes:
- db.ts: Added getClient() for transaction support
- crud.ts: Implemented taskMoveProject() with full transaction
- index.ts: Wired up tool handler and import
- tools/index.ts: Registered tool definition

Preserves:
- Task metadata (title, description, type, status, priority)
- Checklist items
- Linked commits
- Delegations
- Activity history
- Task links (relates_to, blocks, duplicates)
- Epic and version assignments
- Embeddings

Process:
1. Validates source task and target project exist
2. Generates new ID in target project
3. Transfers all related data in transaction
4. Marks old task as completed with reference
5. Creates duplicate link between tasks

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

src/index.ts

@@ -37,7 +37,7 @@ import {
 
 import { testConnection, close } from './db.js';
 import { toolDefinitions } from './tools/index.js';
-import { taskAdd, taskList, taskShow, taskClose, taskUpdate, taskInvestigate } from './tools/crud.js';
+import { taskAdd, taskList, taskShow, taskClose, taskUpdate, taskInvestigate, taskMoveProject } from './tools/crud.js';
 import { taskSimilar, taskContext } from './tools/search.js';
 import { taskLink, checklistAdd, checklistToggle, taskResolveDuplicate } from './tools/relations.js';
 import { epicAdd, epicList, epicShow, epicAssign, epicClose } from './tools/epics.js';
@@ -147,6 +147,13 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
           description: a.description,
         });
         break;
+      case 'task_move_project':
+        result = await taskMoveProject({
+          id: a.id,
+          target_project: a.target_project,
+          reason: a.reason,
+        });
+        break;
 
       // Search
       case 'task_similar':