fix(22): revise plan based on checker feedback

- Add acknowledgment that SESS-02/SESS-03 were verified clean in Phase 19
- Merge Task 2 (verification-only) into Task 1's verify section
- Plan now has 1 auto task producing code artifacts

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

.planning/phases/22-session-screen-fixes/22-01-PLAN.md

@@ -30,6 +30,12 @@ Harden session screen callback cleanup to ensure cleanup runs reliably on all ex
 Purpose: Defensive improvement to SESS-01 finding - ensure callback unregistration works even if normal leave flow doesn't execute (browser crash, navigation away, etc.)
 
 Output: JKSessionScreen.js with improved cleanup reliability using useRef pattern
+
+**Note on SESS-02 and SESS-03:** Phase 19 audit verified these requirements already satisfied:
+- SESS-02: useJamServer.js - All timers properly cleaned up (no issues found)
+- SESS-03: useSessionStats.js, useSessionModel.js - All timers properly cleaned up (no issues found)
+
+Only SESS-01 requires code changes. This plan addresses SESS-01 exclusively.
 </objective>
 
 <execution_context>
@@ -91,54 +97,31 @@ Note: Remove `registeredCallbacks` from the useCallback dependency array since w
   </action>
   <verify>
 1. Run `npm run lint` in jam-ui directory - should pass (or have no new lint errors)
-2. Manually verify the code changes match the pattern described
-3. Run existing tests: `cd jam-ui && npm test -- --grep "session"` (if any session tests exist)
+2. Run `cd jam-ui && npm run build` - builds successfully
+3. Verify the code changes match the pattern described:
+   - registeredCallbacksRef declared alongside registeredCallbacks state
+   - unregisterMessageCallbacks uses ref instead of state for cleanup
+   - Callback registration stores to both state and ref
+4. Run existing tests: `cd jam-ui && npm test -- --grep "session"` (if any session tests exist)
+5. Trace through exit path logic to confirm cleanup works:
+   - Normal leave flow (Leave button): handleLeaveSubmit → unregisterMessageCallbacks() → ref cleared, state cleared
+   - Navigation away (browser back, route change): unmount → useEffect cleanup → unregisterMessageCallbacks() → ref has callbacks → callbacks unregistered
+   - Browser close/crash: Connection closes → server handles orphaned connections (out of scope for frontend)
   </verify>
   <done>
 - registeredCallbacksRef declared alongside registeredCallbacks state
 - unregisterMessageCallbacks uses ref instead of state for cleanup
 - Callback registration stores to both state and ref
 - Cleanup will work reliably on all exit paths
-  </done>
-</task>
-
-<task type="auto">
-  <name>Task 2: Document cleanup verification and update plan artifacts</name>
-  <files>N/A (verification task)</files>
-  <action>
-Verify the fix by tracing through the code paths:
-
-1. **Normal leave flow (Leave button):**
-   - User clicks Leave → handleLeaveSubmit runs → unregisterMessageCallbacks() called
-   - Ref is cleared, then state is cleared
-   - useEffect cleanup also runs but ref is empty (no double unregister, which is fine)
-
-2. **Navigation away (browser back, route change):**
-   - Component unmounts → useEffect cleanup runs → unregisterMessageCallbacks() called
-   - Ref has current callbacks → callbacks are unregistered
-   - No memory leak
-
-3. **Browser close/crash:**
-   - Connection closes → jamServer cleanup handles it on server side
-   - This is out of scope for frontend cleanup (server handles orphaned connections)
-
-The fix ensures path 2 (navigation away) works correctly, which was the edge case identified in SESS-01.
-  </action>
-  <verify>
-1. Read through JKSessionScreen.js to confirm changes are correct
-2. Verify the cleanup useEffect at ~line 934 will work with the new ref-based approach
-  </verify>
-  <done>
-- All exit paths verified to trigger cleanup
-- Navigation away path confirmed to work with ref pattern
-- No additional code changes needed
+- Code builds and passes lint
+- Existing tests continue to pass
   </done>
 </task>
 
 </tasks>
 
 <verification>
-After completing all tasks:
+After completing the task:
 
 1. **Lint check:** `cd jam-ui && npm run lint` - no new errors
 2. **Build check:** `cd jam-ui && npm run build` - builds successfully