Step 3: delete the old runs/ runtime infrastructure

With direct code-mode on its own event store/bus (step 1) and rowboat on the
new sessions runtime (step 2), nothing uses the generic runs/ infra anymore.

- delete runs/runs.ts, runs/repo.ts, runs/bus.ts (keep runs/lock.ts +
  runs/abort-registry.ts — the new runtime uses them)
- remove the runs:fetch + runs:events IPC channels, their handlers, the
  bus -> runs:events forwarder (emitRunEvent / startRunsWatcher / stopRunsWatcher)
- drop the now-unused runsRepo + bus DI registrations

The old LLM agent runtime AND its run event-log/bus are now fully gone; chat,
headless, and both code-mode modes run on the new runtime (code-mode direct on
its own dedicated event store + bus).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -21,7 +21,7 @@ import { BrowserStateSchema } from './browser-control.js';
 import { BillingInfoSchema } from './billing.js';
 import { GmailThreadSchema } from './blocks.js';
 import { PermissionDecision, ApprovalPolicy, CodingAgent } from './code-mode.js';
-import { Run, RunEvent } from './runs.js';
+import { RunEvent } from './runs.js';
 import { NotificationSettingsSchema } from './notification-settings.js';
 import { CodeProject, CodeSession, CodeSessionMode, CodeSessionStatus, GitRepoInfo, GitStatusFile } from './code-sessions.js';
 
@@ -238,19 +238,6 @@ const ipcSchemas = {
       result: z.unknown(),
     }),
   },
-  // Code-mode reuses the generic runs event-log + bus (decoupled from the
-  // retired LLM agent runtime): fetch a session's transcript and stream its
-  // live events. Chat + headless use the sessions:* channels instead.
-  'runs:fetch': {
-    req: z.object({
-      runId: z.string(),
-    }),
-    res: Run,
-  },
-  'runs:events': {
-    req: z.null(),
-    res: z.null(),
-  },
   'services:events': {
     req: ServiceEvent,
     res: z.null(),