[ENHANCEMENT] Add privacy-safe telemetry for commit-message generation #292

Problem (one or two sentences)

Maintainers need to understand adoption and failure patterns for commit-message generation without collecting source content.

Part of #145.

Context (who is affected and when)

Git diffs, file paths, branch names, and generated commit messages may contain sensitive project information.

Desired behavior (conceptual, not technical)

Zoo records privacy-safe commit-message generation events.

Constraints / preferences (optional)

Telemetry must not include branch names, file paths, diffs, or generated commit text.

Request checklist

• I've searched existing Issues and Discussions for duplicates
• This describes a specific problem with clear context and impact

Zoo Code Task Links (optional)

No response

Optional (for contributors): You can stop here if you're just proposing the improvement.

Acceptance criteria (optional)

• A telemetry event type is added for commit-message generation.
• Successful generation is captured.
• Failure or cancellation tracking is either added with coarse categories or explicitly deferred.
• No branch name, file path, diff content, or generated message content is sent.
• Type checks or tests cover the new telemetry event.

Proposed approach (optional)

Add a minimal event aligned with existing Zoo telemetry patterns and keep payload fields content-free.

Trade-offs / risks (optional)

Overly detailed telemetry could leak source or workflow information.