feat: integrate 5 feature branches, upstream fixes, and MIME detection fix

Squashed 5 commits:

Features (from 5 feature branches):
- MCP fix, pipe mute, stub recovery
- KAIROS activation, openclaw autonomy
- Daemon/job command hierarchy + cross-platform bg engine

Upstream fixes:
- fix: Bun.hash compatibility
- chore: chrome dependency update
- docs: browser support guide

MIME detection fix:
- Screenshot detectMimeFromBase64(): decode raw bytes from base64
  instead of broken charCodeAt comparison
- Fixes API 400 on Windows (JPEG) and macOS (PNG) screenshots

src/jobs/__tests__/state.test.ts

@@ -0,0 +1,91 @@
+/**
+ * Tests for src/jobs/state.ts
+ *
+ * Uses real temp directories and CLAUDE_CONFIG_DIR env var
+ * instead of mocking fs, to avoid cross-test mock pollution.
+ */
+import { describe, expect, test, beforeEach, afterAll } from 'bun:test'
+import { mkdtempSync, rmSync, readFileSync, existsSync } from 'fs'
+import { join } from 'path'
+import { tmpdir } from 'os'
+
+// ─── setup: real temp dir via env var ──────────────────────────────────────
+
+const tempBase = mkdtempSync(join(tmpdir(), 'jobs-state-test-'))
+
+beforeEach(() => {
+  // Each test gets a fresh config dir
+  const tempHome = mkdtempSync(join(tempBase, 'home-'))
+  process.env.CLAUDE_CONFIG_DIR = tempHome
+})
+
+afterAll(() => {
+  delete process.env.CLAUDE_CONFIG_DIR
+  try {
+    rmSync(tempBase, { recursive: true, force: true })
+  } catch {
+    // best-effort cleanup
+  }
+})
+
+// ─── import ─────────────────────────────────────────────────────────────────
+
+const { createJob, readJobState, appendJobReply, getJobDir } = await import(
+  '../state.js'
+)
+
+// ─── tests ──────────────────────────────────────────────────────────────────
+
+describe('createJob', () => {
+  test('creates job directory and writes state, template, and input files', () => {
+    const dir = createJob('job-1', 'my-template', '# Template', 'hello', [
+      '--flag',
+    ])
+    expect(dir).toContain('job-1')
+    expect(existsSync(dir)).toBe(true)
+
+    const stateFile = join(dir, 'state.json')
+    expect(existsSync(stateFile)).toBe(true)
+    const state = JSON.parse(readFileSync(stateFile, 'utf-8'))
+    expect(state.jobId).toBe('job-1')
+    expect(state.templateName).toBe('my-template')
+    expect(state.status).toBe('created')
+    expect(state.args).toEqual(['--flag'])
+
+    expect(readFileSync(join(dir, 'template.md'), 'utf-8')).toBe('# Template')
+    expect(readFileSync(join(dir, 'input.txt'), 'utf-8')).toBe('hello')
+  })
+})
+
+describe('readJobState', () => {
+  test('returns null when job does not exist', () => {
+    expect(readJobState('nonexistent')).toBeNull()
+  })
+
+  test('returns parsed state when job exists', () => {
+    createJob('job-2', 'tpl', 'content', 'input', [])
+    const result = readJobState('job-2')
+    expect(result).not.toBeNull()
+    expect(result!.jobId).toBe('job-2')
+    expect(result!.status).toBe('created')
+  })
+})
+
+describe('appendJobReply', () => {
+  test('returns false when job does not exist', () => {
+    expect(appendJobReply('no-job', 'hello')).toBe(false)
+  })
+
+  test('appends reply and updates state', () => {
+    createJob('job-3', 'tpl', 'content', 'input', [])
+
+    const result = appendJobReply('job-3', 'my reply')
+    expect(result).toBe(true)
+
+    const dir = getJobDir('job-3')
+    const repliesPath = join(dir, 'replies.jsonl')
+    expect(existsSync(repliesPath)).toBe(true)
+    const replyLine = JSON.parse(readFileSync(repliesPath, 'utf-8').trim())
+    expect(replyLine.text).toBe('my reply')
+  })
+})