feat(CF-524): Add project_archive MCP method

Implements complete project archival workflow:
- Migration 024: Add archival fields to projects table
- New project-archive.ts tool coordinating:
  * Tarball creation via shell
  * S3 upload with vault credentials
  * Database metadata tracking
  * Optional local deletion
  * Cleanup of temp files
- Registered in tool definitions and handlers

Replaces manual archival process used for Fireberries/CyprusPulse.

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

src/index.ts

@@ -83,6 +83,7 @@ import {
   sessionPatternDetection,
 } from './tools/session-docs.js';
 import { archiveAdd, archiveSearch, archiveList, archiveGet } from './tools/archives.js';
+import { projectArchive } from './tools/project-archive.js';
 
 // Create MCP server
 const server = new Server(
@@ -667,6 +668,16 @@ server.setRequestHandler(CallToolRequestSchema, async (request) => {
         });
         break;
 
+      // Project archival
+      case 'project_archive':
+        result = await projectArchive({
+          project_key: a.project_key,
+          project_path: a.project_path,
+          delete_local: a.delete_local,
+          session_id: a.session_id,
+        });
+        break;
+
       default:
         throw new Error(`Unknown tool: ${name}`);
     }