feat: enhance terminal bridge and session controls

[cipriandrei10]

This PR enhances the terminal bridge and session management to improve the interaction between chat interfaces and underlying AI tools (Claude, Codex, Gemini, Pi, Kimi). It introduces a system prompt injection mechanism, adds a convenient session kill switch, and provides comprehensive test coverage for these new features.

Key Changes:

• Terminal Bridge Prompt Injection:
  • Added a system prompt injection mechanism ([touchgrass] This is a terminal bridge...) to inform AI tools they are being proxied.
  • For Claude and Codex, the prompt is injected via the --append-system-prompt flag using a temporary file.
  • For Gemini, Pi, and Kimi, a fallback mechanism writes the prompt directly to the terminal PTY upon detecting the initial tool prompt (e.g., > or ? ).
  • Refactored prompt detection into testable helpers in run.ts.
• Session Kill Switch:
  • Implemented a "kill switch" in the chat interface: sending /q or stop (case-insensitive) now triggers an immediate interruption and stops the active session.
• Improved Session Resilience:
  • Refactored getRecoveryName to safely handle undefined remoteId during session recovery.
  • Ensured cleanup of temporary bridge prompt files after session termination.
  • Fixed scope issues for session resume variables in the main run loop.
• Testing:
  • New packages/cli/src/tests/bridge-prompt.test.ts: Verifies the logic for terminal bridge prompt detection across different tools.
  • New packages/cli/src/tests/stdin-input.test.ts: Validates the /q kill switch and file mention prepending.
  • Updated packages/cli/src/tests/codex-args.test.ts: Ensures correct argument parsing for resume and restart scenarios.