Backend chat observability upgrade: standardized request summary logs

[akgohain]

Motivation

• Provide a concise, structured single-line summary for chat/helper endpoints to speed diagnosis of stalls and failures.
• Ensure every request summary includes request_id, endpoint, latency_ms, status, and error_type while preserving existing verbose logs.
• Avoid leaking sensitive request payloads in summary logs.

Description

• Added a shared logging utility server_api/chatbot/logging_utils.py exposing request_id_from_request and log_request_summary that emits a standardized one-line summary with the required fields.
• Integrated summary logging into chat endpoints in server_api/main.py (/chat/query, /chat/clear, /chat/status, /chat/helper/query, /chat/helper/clear) capturing start time, status (ok/error), and error type without logging request bodies.
• Kept original endpoint behavior and persistence logic unchanged while adding try/except/finally around processing to ensure the summary is always emitted.
• Changes implemented on branch agent/chat-observability-upgrade and include a new test file tests/test_chat_logging_fields.py.

Testing

• Added tests/test_chat_logging_fields.py which asserts presence of request_id, endpoint, latency_ms, status, and error_type in summary logs and verifies sensitive payload text is not present.
• Attempted environment uv run pytest -q tests/test_chat_logging_fields.py which failed in this environment due to editable dependency metadata for pytorch_connectomics (environment-specific), but the targeted test run PYTHONPATH=. pytest -q tests/test_chat_logging_fields.py executed successfully.
• Result: tests/test_chat_logging_fields.py passed (2 passed).

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Codex Task

[akgohain]

Consolidated into draft PR #165 (feat/codex-wave-integration). Closing this source draft to keep review in one place.