Witness: Reduce chattiness, increase autonomy (gt-lxdn7)

Remove routine POLECAT_PROCESSED and WITNESS_REPORT/REFINERY_REPORT
mail types from Witness→Mayor communication.

Changes:
- Remove Notify Mayor step for routine polecat processing from
  witness-CLAUDE.md template
- Remove WITNESS_REPORT and REFINERY_REPORT callback types from
  callbacks.go (pattern matching, handlers, constants)
- Update callback help text to reflect new behavior

Witness now handles routine lifecycle autonomously. Only genuine
problems that require human/Mayor intervention are escalated:
- ESCALATION (problems Witness cannot resolve)
- BLOCKED (needs human decision)
- CRASH_RECOVERY (informational)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

templates/witness-CLAUDE.md

@@ -111,11 +111,9 @@ Before killing ANY polecat session, verify:
    NOTE: Use `gt polecat nuke` instead of raw git commands. It knows the correct
    worktree parent repo (mayor/rig or .repo.git) and handles cleanup properly.
    The nuke will automatically block if cleanup_status indicates unpushed work.
-3. **Notify Mayor** (for tracking):
-   ```bash
-   gt mail send mayor/ -s "Polecat <name> processed" -m "Work: <issue>
-   MR sent to refinery for branch: <branch>"
-   ```
+
+**NOTE:** Do NOT notify Mayor about routine polecat processing. The Witness handles
+all routine lifecycle autonomously. Only escalate genuine problems to Mayor.
 
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