feat: add host-driven GitHub Actions CI watcher (Level 3)

Replace LLM-per-tick polling with direct `gh api` calls for GitHub
Actions watchers. New `ci_provider` discriminator column routes tasks
to either the host-driven path (zero LLM tokens) or the existing
generic LLM path. GitHub watchers poll at 15s intervals (min 10s)
via `checkGitHubActionsRun()` in the scheduler, with completion
messages sent directly to chat on terminal state.

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

src/github-ci.test.ts

@@ -0,0 +1,149 @@
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+const { execFileMock } = vi.hoisted(() => ({
+  execFileMock: vi.fn(),
+}));
+
+vi.mock('child_process', () => ({
+  execFile: execFileMock,
+}));
+
+import {
+  checkGitHubActionsRun,
+  parseGitHubCiMetadata,
+  serializeGitHubCiMetadata,
+} from './github-ci.js';
+
+describe('github-ci helpers', () => {
+  afterEach(() => {
+    execFileMock.mockReset();
+  });
+
+  it('round-trips GitHub CI metadata', () => {
+    const raw = serializeGitHubCiMetadata({
+      repo: 'owner/repo',
+      run_id: 123456,
+      poll_count: 1,
+    });
+
+    expect(parseGitHubCiMetadata(raw)).toEqual({
+      repo: 'owner/repo',
+      run_id: 123456,
+      poll_count: 1,
+      consecutive_errors: undefined,
+    });
+    expect(parseGitHubCiMetadata('{"repo":"","run_id":0}')).toBeNull();
+  });
+
+  it('returns non-terminal status for in-progress runs', async () => {
+    execFileMock.mockImplementation(
+      (
+        _cmd: string,
+        _args: string[],
+        _opts: unknown,
+        cb: (error: Error | null, stdout: string, stderr: string) => void,
+      ) => {
+        cb(
+          null,
+          JSON.stringify({
+            status: 'in_progress',
+            conclusion: null,
+          }),
+          '',
+        );
+      },
+    );
+
+    await expect(
+      checkGitHubActionsRun({
+        prompt: `
+[BACKGROUND CI WATCH]
+
+Watch target:
+GitHub Actions run 123456
+
+Task ID:
+task-github
+
+Check instructions:
+Managed by host-driven watcher.
+        `.trim(),
+        ci_metadata: JSON.stringify({
+          repo: 'owner/repo',
+          run_id: 123456,
+        }),
+      }),
+    ).resolves.toEqual({
+      terminal: false,
+      resultSummary: 'GitHub Actions run 123456 is in_progress',
+    });
+  });
+
+  it('renders a concise completion message for terminal runs', async () => {
+    execFileMock
+      .mockImplementationOnce(
+        (
+          _cmd: string,
+          _args: string[],
+          _opts: unknown,
+          cb: (error: Error | null, stdout: string, stderr: string) => void,
+        ) => {
+          cb(
+            null,
+            JSON.stringify({
+              status: 'completed',
+              conclusion: 'failure',
+              name: 'CI',
+              html_url: 'https://github.com/owner/repo/actions/runs/654321',
+              head_branch: 'main',
+            }),
+            '',
+          );
+        },
+      )
+      .mockImplementationOnce(
+        (
+          _cmd: string,
+          _args: string[],
+          _opts: unknown,
+          cb: (error: Error | null, stdout: string, stderr: string) => void,
+        ) => {
+          cb(
+            null,
+            JSON.stringify({
+              jobs: [
+                { name: 'build', conclusion: 'success' },
+                { name: 'test', conclusion: 'failure' },
+              ],
+            }),
+            '',
+          );
+        },
+      );
+
+    const result = await checkGitHubActionsRun({
+      prompt: `
+[BACKGROUND CI WATCH]
+
+Watch target:
+GitHub Actions run 654321
+
+Task ID:
+task-github
+
+Check instructions:
+Managed by host-driven watcher.
+      `.trim(),
+      ci_metadata: JSON.stringify({
+        repo: 'owner/repo',
+        run_id: 654321,
+      }),
+    });
+
+    expect(result.terminal).toBe(true);
+    expect(result.resultSummary).toContain('실패');
+    expect(result.completionMessage).toContain('CI 완료: GitHub Actions run 654321');
+    expect(result.completionMessage).toContain('판정: 실패');
+    expect(result.completionMessage).toContain('- 실패 job: test');
+  });
+});