fix(planner): commit revised plans after checker feedback

Revision mode was missing git commit step - plans updated based on
checker issues were written to disk but never committed.

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

agents/gsd-planner.md

@@ -949,7 +949,14 @@ After making edits, self-check:
 - [ ] Dependencies still correct
 - [ ] Files on disk updated (use Write tool)
 
-### Step 6: Return Revision Summary
+### Step 6: Commit Revised Plans
+
+```bash
+git add .planning/phases/${PHASE}-*/${PHASE}-*-PLAN.md
+git commit -m "fix(${PHASE}): revise plans based on checker feedback"
+```
+
+### Step 7: Return Revision Summary
 
 ```markdown
 ## REVISION COMPLETE