Cap diagnostic log payloads

[etraut-openai]

Why

This PR caps risky diagnostic payloads before emitting tracing events, so every log sink receives a bounded value that's limited to 16K (keeping head and tail and truncating in the middle).

What Changed

This adds codex-utils-log, a small utility crate for rendering diagnostic payloads with a bounded head/tail preview. Oversized values include original_bytes, shown_bytes, omitted_bytes, and a sha256 digest so logs remain useful for correlation without storing the whole payload.

It also caps no-newline MCP stderr buffering before those bytes are logged.

Affected Log Points

• MCP client notifications: logging/message data/logger plus cancelled/progress/resource-update fields.
• MCP stderr: local stdio and executor-backed stderr, including no-newline stderr streams.
• Core turn diagnostics: MCP tool-call errors, turn errors, submission debug logs, non-tool output item debug logs, and realtime conversation events.
• App-server JSON-RPC/events: unexpected incoming notifications/responses/errors, outbound server notifications, and send/callback errors that can include queued payloads.
• Codex API wire diagnostics: Responses SSE/websocket payload logs, realtime call/websocket payload logs, unsupported/parse-failure realtime event payloads, and model-list decode failure bodies.
• TUI/app diagnostics: turn diff logs, pasted image path logs, panic hook payloads, app-server enqueue/send errors, and markdown stream delta traces.
• Auth/analytics response bodies: token refresh failures, server error parsing, and analytics event request failure bodies.

Verification

• cargo test -p codex-utils-log
• cargo test -p codex-rmcp-client stderr_log
• cargo check -p codex-core -p codex-tui -p codex-app-server -p codex-login -p codex-analytics
• just fix -p codex-utils-log -p codex-rmcp-client -p codex-core -p codex-tui -p codex-app-server -p codex-api -p codex-login -p codex-analytics
• just bazel-lock-check

[etraut-openai]

@codex review

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 83e56dfc5e

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[etraut-openai]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Keep it up!

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".