feat: eager vLLM warmup and smart page titles in paginate stage

- Add warmup() to LlmProvider interface for eager subprocess startup
- ManagedVllmProvider.warmup() starts vLLM in background on project load
- ProviderRegistry.warmupAll() triggers all managed providers
- NamedProvider proxies warmup() to inner provider
- paginate stage generates LLM-powered descriptive page titles when
  available, cached by content hash, falls back to generic "Page N"
- project-mcp-endpoint calls warmupAll() on router creation so vLLM
  is loading while the session initializes

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

src/cli/package.json

@@ -21,6 +21,7 @@
     "@mcpctl/shared": "workspace:*",
     "chalk": "^5.4.0",
     "commander": "^13.0.0",
+    "diff": "^8.0.3",
     "ink": "^6.8.0",
     "inquirer": "^12.0.0",
     "js-yaml": "^4.1.0",
@@ -28,6 +29,7 @@
     "zod": "^3.24.0"
   },
   "devDependencies": {
+    "@types/diff": "^8.0.0",
     "@types/js-yaml": "^4.0.9",
     "@types/node": "^25.3.0",
     "@types/react": "^19.2.14"