fix: Resolve agent workdir probing for initiative project subdirectories

Conflict-resolution agents (and any initiative-based agent) can write
.cw/output/signal.json inside a project subdirectory (e.g.
agent-workdirs/<name>/codewalk-district/.cw/output/) rather than the
parent agent workdir. This caused two failures:

1. spawnInternal wrote spawn-diagnostic.json before registering the
   agent in activeAgents and starting pollForCompletion. If the .cw/
   directory didn't exist (no inputContext provided), the write threw
   ENOENT, orphaning the running process with no completion monitoring.

2. resolveAgentCwd in cleanup-manager and output-handler only probed
   for a workspace/ subdirectory (standalone agents) but not project
   subdirectories, so reconciliation and completion handling couldn't
   find signal.json and marked the agent as crashed.

Fixes:
- Move activeAgents registration and pollForCompletion setup before
  the diagnostic write; make the write non-fatal with mkdir -p
- Add project subdirectory probing to resolveAgentCwd in both
  cleanup-manager.ts and output-handler.ts

apps/server/agent/output-handler.ts

@@ -7,7 +7,7 @@
  */
 
 import { readFile } from 'node:fs/promises';
-import { existsSync } from 'node:fs';
+import { existsSync, readdirSync } from 'node:fs';
 import { join } from 'node:path';
 import type { AgentRepository } from '../db/repositories/agent-repository.js';
 import type { ChangeSetRepository, CreateChangeSetEntryData } from '../db/repositories/change-set-repository.js';
@@ -233,10 +233,10 @@ export class OutputHandler {
 
       log.debug({ agentId }, 'detached agent completed');
 
-      // Resolve actual agent working directory — standalone agents run in a
-      // "workspace/" subdirectory inside getAgentWorkdir, so prefer agentCwd
-      // recorded at spawn time when available.
-      const agentWorkdir = active?.agentCwd ?? getAgentWorkdir(agent.worktreeId);
+      // Resolve actual agent working directory.
+      // The recorded agentCwd may be the parent dir (agent-workdirs/<name>/) while
+      // the agent actually writes .cw/output/ inside a project subdirectory.
+      const agentWorkdir = this.resolveAgentWorkdir(active?.agentCwd ?? getAgentWorkdir(agent.worktreeId));
       const outputDir = join(agentWorkdir, '.cw', 'output');
       const expectedPwdFile = join(agentWorkdir, '.cw', 'expected-pwd.txt');
       const diagnosticFile = join(agentWorkdir, '.cw', 'spawn-diagnostic.json');
@@ -1158,6 +1158,31 @@ export class OutputHandler {
     }
   }
 
+  /**
+   * Resolve the actual agent working directory. The recorded agentCwd may be
+   * the parent (agent-workdirs/<name>/) but .cw/output/ could be inside a
+   * project subdirectory (e.g. codewalk-district/.cw/output/).
+   */
+  private resolveAgentWorkdir(base: string): string {
+    if (existsSync(join(base, '.cw', 'output'))) return base;
+
+    // Standalone agents: workspace/ subdirectory
+    const workspaceSub = join(base, 'workspace');
+    if (existsSync(join(workspaceSub, '.cw'))) return workspaceSub;
+
+    // Initiative-based agents: probe project subdirectories
+    try {
+      for (const entry of readdirSync(base, { withFileTypes: true })) {
+        if (entry.isDirectory() && entry.name !== '.cw') {
+          const sub = join(base, entry.name);
+          if (existsSync(join(sub, '.cw', 'output'))) return sub;
+        }
+      }
+    } catch { /* base may not exist */ }
+
+    return base;
+  }
+
   private emitCrashed(agent: { id: string; name: string; taskId: string | null }, error: string): void {
     if (this.eventBus) {
       const event: AgentCrashedEvent = {