worktree セッション引き継ぎ機能を追加

同じ worktree に再度指示を出す際、前回のセッションを引き継げるようにする。

- loadWorktreeSessions / updateWorktreeSession を追加
- worktree 別にエージェントセッションを保存（.takt/logs/worktree-sessions/）
- workflowExecution で worktree でもセッション管理を有効化

src/__tests__/config.test.ts

@@ -20,6 +20,12 @@ import {
   addToInputHistory,
   getInputHistoryPath,
   MAX_INPUT_HISTORY,
+  // Worktree session functions
+  getWorktreeSessionsDir,
+  encodeWorktreePath,
+  getWorktreeSessionPath,
+  loadWorktreeSessions,
+  updateWorktreeSession,
 } from '../config/paths.js';
 import { loadProjectConfig } from '../config/projectConfig.js';
 
@@ -417,3 +423,201 @@ describe('saveProjectConfig - gitignore copy', () => {
     expect(content).toBe(customContent);
   });
 });
+
+// ============ Worktree Sessions ============
+
+describe('encodeWorktreePath', () => {
+  it('should replace slashes with dashes', () => {
+    const encoded = encodeWorktreePath('/project/.takt/worktrees/my-task');
+
+    expect(encoded).not.toContain('/');
+    expect(encoded).toContain('-');
+  });
+
+  it('should handle Windows-style paths', () => {
+    const encoded = encodeWorktreePath('C:\\project\\worktrees\\task');
+
+    expect(encoded).not.toContain('\\');
+    expect(encoded).not.toContain(':');
+  });
+
+  it('should produce consistent output for same input', () => {
+    const path = '/project/.takt/worktrees/feature-x';
+    const encoded1 = encodeWorktreePath(path);
+    const encoded2 = encodeWorktreePath(path);
+
+    expect(encoded1).toBe(encoded2);
+  });
+});
+
+describe('getWorktreeSessionsDir', () => {
+  let testDir: string;
+
+  beforeEach(() => {
+    testDir = join(tmpdir(), `takt-test-${randomUUID()}`);
+    mkdirSync(testDir, { recursive: true });
+  });
+
+  afterEach(() => {
+    if (existsSync(testDir)) {
+      rmSync(testDir, { recursive: true, force: true });
+    }
+  });
+
+  it('should return path inside .takt directory', () => {
+    const sessionsDir = getWorktreeSessionsDir(testDir);
+
+    expect(sessionsDir).toContain('.takt');
+    expect(sessionsDir).toContain('worktree-sessions');
+  });
+});
+
+describe('getWorktreeSessionPath', () => {
+  let testDir: string;
+
+  beforeEach(() => {
+    testDir = join(tmpdir(), `takt-test-${randomUUID()}`);
+    mkdirSync(testDir, { recursive: true });
+  });
+
+  afterEach(() => {
+    if (existsSync(testDir)) {
+      rmSync(testDir, { recursive: true, force: true });
+    }
+  });
+
+  it('should return .json file path', () => {
+    const sessionPath = getWorktreeSessionPath(testDir, '/worktree/path');
+
+    expect(sessionPath).toMatch(/\.json$/);
+  });
+
+  it('should include encoded worktree path in filename', () => {
+    const worktreePath = '/project/.takt/worktrees/my-feature';
+    const sessionPath = getWorktreeSessionPath(testDir, worktreePath);
+
+    expect(sessionPath).toContain('worktree-sessions');
+  });
+});
+
+describe('loadWorktreeSessions', () => {
+  let testDir: string;
+
+  beforeEach(() => {
+    testDir = join(tmpdir(), `takt-test-${randomUUID()}`);
+    mkdirSync(testDir, { recursive: true });
+  });
+
+  afterEach(() => {
+    if (existsSync(testDir)) {
+      rmSync(testDir, { recursive: true, force: true });
+    }
+  });
+
+  it('should return empty object when no session file exists', () => {
+    const sessions = loadWorktreeSessions(testDir, '/some/worktree');
+
+    expect(sessions).toEqual({});
+  });
+
+  it('should load saved sessions from file', () => {
+    const worktreePath = '/project/worktree';
+    const sessionsDir = getWorktreeSessionsDir(testDir);
+    mkdirSync(sessionsDir, { recursive: true });
+
+    const sessionPath = getWorktreeSessionPath(testDir, worktreePath);
+    const data = {
+      agentSessions: { coder: 'session-123', reviewer: 'session-456' },
+      updatedAt: new Date().toISOString(),
+    };
+    writeFileSync(sessionPath, JSON.stringify(data));
+
+    const sessions = loadWorktreeSessions(testDir, worktreePath);
+
+    expect(sessions).toEqual({ coder: 'session-123', reviewer: 'session-456' });
+  });
+
+  it('should return empty object for corrupted JSON', () => {
+    const worktreePath = '/project/worktree';
+    const sessionsDir = getWorktreeSessionsDir(testDir);
+    mkdirSync(sessionsDir, { recursive: true });
+
+    const sessionPath = getWorktreeSessionPath(testDir, worktreePath);
+    writeFileSync(sessionPath, 'not valid json');
+
+    const sessions = loadWorktreeSessions(testDir, worktreePath);
+
+    expect(sessions).toEqual({});
+  });
+});
+
+describe('updateWorktreeSession', () => {
+  let testDir: string;
+
+  beforeEach(() => {
+    testDir = join(tmpdir(), `takt-test-${randomUUID()}`);
+    mkdirSync(testDir, { recursive: true });
+  });
+
+  afterEach(() => {
+    if (existsSync(testDir)) {
+      rmSync(testDir, { recursive: true, force: true });
+    }
+  });
+
+  it('should create session file if not exists', () => {
+    const worktreePath = '/project/worktree';
+
+    updateWorktreeSession(testDir, worktreePath, 'coder', 'session-abc');
+
+    const sessions = loadWorktreeSessions(testDir, worktreePath);
+    expect(sessions).toEqual({ coder: 'session-abc' });
+  });
+
+  it('should update existing session', () => {
+    const worktreePath = '/project/worktree';
+
+    updateWorktreeSession(testDir, worktreePath, 'coder', 'session-1');
+    updateWorktreeSession(testDir, worktreePath, 'coder', 'session-2');
+
+    const sessions = loadWorktreeSessions(testDir, worktreePath);
+    expect(sessions.coder).toBe('session-2');
+  });
+
+  it('should preserve other agent sessions when updating one', () => {
+    const worktreePath = '/project/worktree';
+
+    updateWorktreeSession(testDir, worktreePath, 'coder', 'coder-session');
+    updateWorktreeSession(testDir, worktreePath, 'reviewer', 'reviewer-session');
+
+    const sessions = loadWorktreeSessions(testDir, worktreePath);
+    expect(sessions).toEqual({
+      coder: 'coder-session',
+      reviewer: 'reviewer-session',
+    });
+  });
+
+  it('should create worktree-sessions directory if not exists', () => {
+    const worktreePath = '/project/worktree';
+    const sessionsDir = getWorktreeSessionsDir(testDir);
+    expect(existsSync(sessionsDir)).toBe(false);
+
+    updateWorktreeSession(testDir, worktreePath, 'coder', 'session-xyz');
+
+    expect(existsSync(sessionsDir)).toBe(true);
+  });
+
+  it('should keep sessions isolated between different worktrees', () => {
+    const worktree1 = '/project/worktree-1';
+    const worktree2 = '/project/worktree-2';
+
+    updateWorktreeSession(testDir, worktree1, 'coder', 'wt1-session');
+    updateWorktreeSession(testDir, worktree2, 'coder', 'wt2-session');
+
+    const sessions1 = loadWorktreeSessions(testDir, worktree1);
+    const sessions2 = loadWorktreeSessions(testDir, worktree2);
+
+    expect(sessions1.coder).toBe('wt1-session');
+    expect(sessions2.coder).toBe('wt2-session');
+  });
+});

src/commands/workflowExecution.ts

@@ -5,7 +5,12 @@
 import { WorkflowEngine } from '../workflow/engine.js';
 import type { WorkflowConfig, Language } from '../models/types.js';
 import type { IterationLimitRequest } from '../workflow/types.js';
-import { loadAgentSessions, updateAgentSession } from '../config/paths.js';
+import {
+  loadAgentSessions,
+  updateAgentSession,
+  loadWorktreeSessions,
+  updateWorktreeSession,
+} from '../config/paths.js';
 import {
   header,
   info,
@@ -103,17 +108,18 @@ export async function executeWorkflow(
     displayRef.current.createHandler()(event);
   };
 
-  // Load saved agent sessions for continuity (from project root)
-  // When running in a worktree (cwd !== projectCwd), skip session resume because
-  // Claude Code sessions are stored per-cwd in ~/.claude/projects/{encoded-path}/
-  // and sessions from the main project dir can't be resumed in a worktree dir.
+  // Load saved agent sessions for continuity (from project root or worktree-specific storage)
   const isWorktree = cwd !== projectCwd;
-  const savedSessions = isWorktree ? {} : loadAgentSessions(projectCwd);
+  const savedSessions = isWorktree
+    ? loadWorktreeSessions(projectCwd, cwd)
+    : loadAgentSessions(projectCwd);
 
-  // Session update handler - persist session IDs when they change (to project root)
-  // Skip persisting worktree sessions since they can't be reused across different worktrees.
+  // Session update handler - persist session IDs when they change
+  // Worktree sessions are stored separately per worktree path
   const sessionUpdateHandler = isWorktree
-    ? undefined
+    ? (agentName: string, agentSessionId: string): void => {
+        updateWorktreeSession(projectCwd, cwd, agentName, agentSessionId);
+      }
     : (agentName: string, agentSessionId: string): void => {
         updateAgentSession(projectCwd, agentName, agentSessionId);
       };

src/config/paths.ts

@@ -98,4 +98,10 @@ export {
   saveAgentSessions,
   updateAgentSession,
   clearAgentSessions,
+  // Worktree sessions
+  getWorktreeSessionsDir,
+  encodeWorktreePath,
+  getWorktreeSessionPath,
+  loadWorktreeSessions,
+  updateWorktreeSession,
 } from './sessionStore.js';

src/config/sessionStore.ts

@@ -170,6 +170,76 @@ export function clearAgentSessions(projectDir: string): void {
   clearClaudeProjectSessions(projectDir);
 }
 
+// ============ Worktree Sessions ============
+
+/** Get the worktree sessions directory */
+export function getWorktreeSessionsDir(projectDir: string): string {
+  return join(getProjectConfigDir(projectDir), 'worktree-sessions');
+}
+
+/** Encode a worktree path to a safe filename */
+export function encodeWorktreePath(worktreePath: string): string {
+  const resolved = resolve(worktreePath);
+  return resolved.replace(/[/\\:]/g, '-');
+}
+
+/** Get path for a worktree's session file */
+export function getWorktreeSessionPath(projectDir: string, worktreePath: string): string {
+  const dir = getWorktreeSessionsDir(projectDir);
+  const encoded = encodeWorktreePath(worktreePath);
+  return join(dir, `${encoded}.json`);
+}
+
+/** Load saved agent sessions for a worktree */
+export function loadWorktreeSessions(
+  projectDir: string,
+  worktreePath: string
+): Record<string, string> {
+  const sessionPath = getWorktreeSessionPath(projectDir, worktreePath);
+  if (existsSync(sessionPath)) {
+    try {
+      const content = readFileSync(sessionPath, 'utf-8');
+      const data = JSON.parse(content) as AgentSessionData;
+      return data.agentSessions || {};
+    } catch {
+      return {};
+    }
+  }
+  return {};
+}
+
+/** Update a single agent session for a worktree (atomic) */
+export function updateWorktreeSession(
+  projectDir: string,
+  worktreePath: string,
+  agentName: string,
+  sessionId: string
+): void {
+  const dir = getWorktreeSessionsDir(projectDir);
+  ensureDir(dir);
+
+  const sessionPath = getWorktreeSessionPath(projectDir, worktreePath);
+  let sessions: Record<string, string> = {};
+
+  if (existsSync(sessionPath)) {
+    try {
+      const content = readFileSync(sessionPath, 'utf-8');
+      const data = JSON.parse(content) as AgentSessionData;
+      sessions = data.agentSessions || {};
+    } catch {
+      sessions = {};
+    }
+  }
+
+  sessions[agentName] = sessionId;
+
+  const data: AgentSessionData = {
+    agentSessions: sessions,
+    updatedAt: new Date().toISOString(),
+  };
+  writeFileAtomic(sessionPath, JSON.stringify(data, null, 2));
+}
+
 /**
  * Get the Claude CLI project session directory path.
  * Claude CLI stores sessions in ~/.claude/projects/{encoded-project-path}/