feat: normalized external-agent status (#10 scoped) (v2.7.6)

Scoped half of boocode_code_review_v2 §1 #10 — publish the agent status
BooCoder already observes (the config-injection notify-hook is the documented
follow-on, clean-room from superset ELv2).

- agent_status_updated WS frame (working|blocked|idle|error), server+web parity.
- Published from the dispatcher's turn boundaries (warm-acp/opencode/sdk/pty:
  working at start, idle/error at end) + the permission flow (blocked/working).
  Best-effort, never breaks a turn.
- Clean-room normalizeAgentEvent helper (superset's vendor-event -> Start/blocked
  /Stop collapse, event names as facts) + 25 tests — reused by the follow-on.
- AgentComposerBar status dot (distinct from the WS-liveness dot), tracked per
  (chat,agent) by a useAgentStatus map in CoderPane.

Built by 2 parallel agents vs a pinned frame contract. Server 545 + coder 294
tests passing (25 new); web tsc + builds clean; ws-frames parity green. Clears
the actionable review backlog (#1/#3/#4/#6-#12). Builds on v2.7.5.

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

apps/coder/src/services/__tests__/normalize-agent-status.test.ts

@@ -0,0 +1,83 @@
+import { describe, it, expect } from 'vitest';
+import { normalizeAgentEvent } from '../normalize-agent-status.js';
+
+describe('normalizeAgentEvent', () => {
+  describe('working bucket', () => {
+    const cases = [
+      'SessionStart',
+      'UserPromptSubmit',
+      'UserPromptSubmitted',
+      'PostToolUse',
+      'PostToolUseFailure',
+      'BeforeAgent',
+      'AfterTool',
+      'task_started',
+    ];
+    for (const name of cases) {
+      it(`maps ${name} → working`, () => {
+        expect(normalizeAgentEvent(name)).toBe('working');
+      });
+    }
+  });
+
+  describe('blocked bucket', () => {
+    const cases = [
+      'PreToolUse',
+      'Notification',
+      'PermissionRequest',
+      'exec_approval_request',
+      'apply_patch_approval_request',
+      'request_user_input',
+    ];
+    for (const name of cases) {
+      it(`maps ${name} → blocked`, () => {
+        expect(normalizeAgentEvent(name)).toBe('blocked');
+      });
+    }
+  });
+
+  describe('done bucket', () => {
+    const cases = [
+      'Stop',
+      'AfterAgent',
+      'SessionEnd',
+      'task_complete',
+      'agent-turn-complete',
+    ];
+    for (const name of cases) {
+      it(`maps ${name} → done`, () => {
+        expect(normalizeAgentEvent(name)).toBe('done');
+      });
+    }
+  });
+
+  describe('unknown / nullish → null', () => {
+    it('returns null for an unrecognized event', () => {
+      expect(normalizeAgentEvent('SomeRandomEvent')).toBeNull();
+    });
+    it('returns null for empty string', () => {
+      expect(normalizeAgentEvent('')).toBeNull();
+    });
+    it('returns null for undefined', () => {
+      expect(normalizeAgentEvent(undefined)).toBeNull();
+    });
+  });
+
+  describe('case- and separator-insensitive matching', () => {
+    it('matches snake_case spelling of a PascalCase event', () => {
+      expect(normalizeAgentEvent('session_start')).toBe('working');
+      expect(normalizeAgentEvent('post_tool_use')).toBe('working');
+      expect(normalizeAgentEvent('pre_tool_use')).toBe('blocked');
+    });
+    it('matches camelCase spelling', () => {
+      expect(normalizeAgentEvent('userPromptSubmitted')).toBe('working');
+      expect(normalizeAgentEvent('postToolUse')).toBe('working');
+      expect(normalizeAgentEvent('preToolUse')).toBe('blocked');
+      expect(normalizeAgentEvent('sessionEnd')).toBe('done');
+    });
+    it('matches arbitrary case', () => {
+      expect(normalizeAgentEvent('STOP')).toBe('done');
+      expect(normalizeAgentEvent('notification')).toBe('blocked');
+    });
+  });
+});