Add configurable process lifecycle hooks

[ineedjet]

Summary

Provide configurable hooks for process outcomes instead of hard-coding repository labels or Project column names.

Candidate hooks

• an error outcome can enqueue a diagnostic or fix agent;
• entering the accepted/final state can enqueue a retrospective;
• the retrospective can inspect the issue, review artifacts, feedback, run metadata, and resulting changes;
• hooks must be idempotent and must not recursively trigger themselves.

Acceptance criteria

• A generic event model is defined for error, review, rework, and accepted outcomes.
• Consumers can map repository-specific signals to those events.
• Hook execution records provenance and correlation with the originating process run.
• Retries do not create duplicate fix or retrospective work.
• Recursive and cyclic hook execution is prevented.
• Examples cover an error-to-fix loop and accepted-to-retrospective loop.

Origin

Consolidates former dupmachine/ground-control backlog items #452 and #453.