v0.4.0

Changes

• Add visible chat acknowledgements for Codex card submissions.
• Add ack-only card mode via requires_codex=false or feedback_mode=ack.
• Fall back from message reply to chat send when proactive cards carry a synthetic origin message id.

Verification

• python3 -m unittest -v test_feishu_codex_bridge.py
• python3 -m py_compile feishu_codex_bridge.py test_feishu_codex_bridge.py
• git diff --check