feat: implement MCP registry client with multi-source search

Add registry client that queries Official, Glama, and Smithery MCP
registries with caching, request deduplication, retry logic, and
result ranking/dedup. Includes 53 tests covering all components.

Also fix null priority values in cancelled tasks (19-21) that broke
Task Master, and add new tasks 25-27 for registry completion and
CLI discover/install commands.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cli/package.json

@@ -16,11 +16,12 @@
     "test:run": "vitest run"
   },
   "dependencies": {
-    "commander": "^13.0.0",
+    "@mcpctl/db": "workspace:*",
+    "@mcpctl/shared": "workspace:*",
     "chalk": "^5.4.0",
+    "commander": "^13.0.0",
     "inquirer": "^12.0.0",
     "js-yaml": "^4.1.0",
-    "@mcpctl/shared": "workspace:*",
-    "@mcpctl/db": "workspace:*"
+    "zod": "^3.24.0"
   }
 }