fix: resolve CI test failures on Linux runner

[Tsutomu-miku]

Summary

Fixes CI pipeline failures introduced after PR #13 was merged. The GitHub Actions runner (Linux) caused multiple test failures due to platform-specific assumptions and incorrect test framework imports.

Root Causes & Fixes

1. tests/cli-launch.test.ts — 9 test failures

Cause: All launch tests assumed macOS (darwin) platform, but CI runs on Linux where codexm launch now correctly rejects with "not supported on Linux".
Fix: Added setPlatformForTesting("darwin") in beforeEach/afterEach hooks so launch tests run under simulated macOS environment.

2. tests/codex-cli-runner.test.ts — Cannot find module 'vitest'

Cause: Tests were written with vitest imports, but the project uses @rstest/core.
Fix: Migrated all vi.fn() → rs.fn(), vi.mock() → rs.mock(), vi.useFakeTimers() → rs.useFakeTimers(). Also corrected mock paths.

3. src/main.ts — run command using non-existent API

Cause: store.getCurrentAccountInfo?.() does not exist in the codebase.
Fix: Changed to store.getCurrentStatus() which exists and returns { account_id, ... }.

4. src/main.ts — resolveManagedDesktopState missing parameter

Cause: Function body referenced launchPlatform but it was not declared as a parameter.
Fix: Added launchPlatform: CodexmPlatform = "darwin" as an explicit parameter.

5. src/cli/args.ts & src/cli/help.ts — run command not registered

Fix: Added "run" to command registration and help output.

6. Testability improvements

• codex-cli-watcher.ts: AbortSignal-aware delay(), injectable isProcessAliveImpl
• Test files: fake timers, proper stubs, command-sync test

Changed Files

File	Change
src/main.ts	Fix resolveManagedDesktopState param, fix run command API
src/cli/args.ts	Register run command
src/cli/help.ts	Add run to help text
src/codex-cli-watcher.ts	AbortSignal-aware delay, injectable isProcessAliveImpl
tests/cli-launch.test.ts	Platform override for CI
tests/codex-cli-runner.test.ts	Migrate vitest → @rstest/core
tests/codex-cli-watcher.test.ts	Fake timers, DI for process checks
tests/cli-read-commands.test.ts	Command-sync test, stubs
tests/cli.test.ts	Test config stubs