v0.5.0

Changes

• Added optional FEISHU_CODEX_BACKEND=app-server support using codex app-server JSON-RPC.
• Kept FEISHU_CODEX_BACKEND=exec as the default compatible backend.
• Added optional FEISHU_CODEX_MODEL override.
• Documented the current app-server boundary: thread/turn and streamed replies are supported, while approval requests are declined until Feishu button approval is implemented.

Verification

• python3 -m unittest test_feishu_codex_bridge.py passed.
• codex app-server initialize smoke test passed.