feat(apps): M2 host integration — tools, fetch proxy, LLM, copilot, bundled agents

- checkCapability choke point (D7): tools/llm/copilot access requires the
  capability in the app's manifest; 403 capability_not_declared otherwise
- POST /_rowboat/tools/search|execute: Composio pass-through with the same
  request shape as the builtin, typed error mapping
- POST /_rowboat/fetch: SSRF-guarded proxy (loopback/RFC1918/link-local/ULA/
  *.localhost rejection re-checked per redirect hop, 5MB cap + truncated flag,
  30s timeout, Host/Cookie stripped)
- POST /_rowboat/llm/generate: default-model plumbing, override validated
  against the allowed set, token/concurrency caps, usage attributed
  app_llm_generate/<folder>
- POST /_rowboat/copilot/run: headless run (bg-task tool profile, no shell),
  app-attributed audit turn with origin context, 10-min timeout, 1-per-app cap
- registered M2 routes are POST-only (GETs are D17-exempt and must not reach them)
- bundled agents (§8): strict AppAgentDefinitionSchema, deterministic
  app--<folder>--<name> slugs materialized disabled with sourceApp, manifest
  removals deactivate, app delete removes owned tasks; sourceApp in summaries
- new use cases app_llm_generate / app_copilot_run in runs + analytics enums

apps/x/packages/shared/src/runs.ts

@@ -32,6 +32,8 @@ export const StartEvent = BaseRunEvent.extend({
         "meeting_note",
         "knowledge_sync",
         "code_session",
+        "app_llm_generate",
+        "app_copilot_run",
     ]).optional(),
     subUseCase: z.string().optional(),
 });
@@ -190,6 +192,8 @@ export const UseCase = z.enum([
     "meeting_note",
     "knowledge_sync",
     "code_session",
+    "app_llm_generate",
+    "app_copilot_run",
 ]);
 
 export const Run = z.object({