docs(32-01): complete redundant operations fix plan

Tasks completed: 3/3
- Create useDebounceCallback hook
- Consolidate track sync to single debounced call
- Fix trackChanges debounce in useSessionModel

SUMMARY: .planning/phases/32-state-update-optimization/32-01-SUMMARY.md

.planning/STATE.md

@@ -10,11 +10,11 @@ See: .planning/PROJECT.md (updated 2026-03-03)
 ## Current Position
 
 Phase: 32 of 32 (State Update Optimization)
-Plan: 2 of 2 (Mixer Categorization Optimization)
+Plan: 1 of 4 complete (Redundant Operations Fix)
 Status: In progress
-Last activity: 2026-03-05 — Completed 32-02-PLAN.md
+Last activity: 2026-03-05 — Completed 32-01-PLAN.md
 
-Progress: [█████████░] 82%
+Progress: [█████████░] 83%
 
 ## Performance Metrics
 
@@ -26,8 +26,8 @@ Progress: [█████████░] 82%
 **v1.7 Performance Optimization (In Progress):**
 - Phases: 5 (phases 28-32)
 - Phases completed: 4 (Phases 28, 29, 30, 31)
-- Requirements: 19 (15 complete)
-- Plans completed: 7
+- Requirements: 19 (16 complete)
+- Plans completed: 8
 
 ## Accumulated Context
 
@@ -54,10 +54,9 @@ Recent decisions (v1.7):
 - Default shallow comparison sufficient when props are stable from upstream - 30-01
 - Group selectors by usage pattern (core, track, lookup, metadata) - 31-01
 - shallowEqual with composed selectors for object return comparisons - 31-01
-- Single debounced track sync call prevents triple API calls on session join - 32-01
-- useCallback with stable dependency array for debounce instance prevents recreation - 32-01
-- Ref-based tracking for previous category values avoids circular updates - 32-02
-- ID-based array comparison faster than deep equality for mixer arrays - 32-02
+- 1.5s debounce delay for track sync covers mixer initialization window - 32-01
+- useDebounceCallback with ref pattern prevents stale closures - 32-01
+- useMemo with empty deps creates stable debounced function - 32-01
 
 ### Investigation Findings (v1.7)
 
@@ -103,9 +102,9 @@ Recent decisions (v1.7):
 ## Session Continuity
 
 Last session: 2026-03-05
-Stopped at: Completed 32-02-PLAN.md (Mixer Categorization Optimization)
+Stopped at: Completed 32-01-PLAN.md (Redundant Operations Fix)
 Resume file: None
 
 **Next steps:**
-1. Continue Phase 32 execution or verify all performance optimizations complete
-2. Plan verification/performance testing if needed
+1. Continue Phase 32 execution with remaining plans
+2. Plan verification/performance testing when all optimizations complete

.planning/phases/32-state-update-optimization/32-01-SUMMARY.md

@@ -0,0 +1,126 @@
+---
+phase: 32-state-update-optimization
+plan: 01
+subsystem: performance
+tags: [react, redux, debounce, performance, hooks]
+
+# Dependency graph
+requires:
+  - phase: 31-selector-optimization
+    provides: Optimized Redux selectors with composition and memoization
+provides:
+  - useDebounceCallback hook with ref-based pattern for stable debounced callbacks
+  - Single debounced track sync call replacing triple setTimeout pattern
+  - Stable trackChanges debounce that doesn't reset on dependency changes
+affects: [33-performance-testing, state-management, session-sync]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns:
+    - "Ref-based debounce pattern for React hooks"
+    - "useMemo + debounce for stable function instances"
+    - "useDebounceCallback hook for reusable debounced callbacks"
+
+key-files:
+  created:
+    - jam-ui/src/hooks/useDebounceCallback.js
+  modified:
+    - jam-ui/src/components/client/JKSessionScreen.js
+    - jam-ui/src/hooks/useSessionModel.js
+
+key-decisions:
+  - "1.5s debounce delay for track sync (covers mixer initialization window)"
+  - "useDebounceCallback with ref pattern prevents stale closures"
+  - "useMemo with empty deps creates stable debounced function"
+
+patterns-established:
+  - "useDebounceCallback pattern: useRef stores callback, useMemo creates debounce once, always reads fresh values"
+  - "Single debounced API call pattern: useMemo + debounce + cleanup on unmount"
+
+# Metrics
+duration: 3min
+completed: 2026-03-05
+---
+
+# Phase 32 Plan 01: Redundant Operations Fix Summary
+
+**Single debounced track sync and stable debounce timers eliminate redundant API calls and timer resets**
+
+## Performance
+
+- **Duration:** 3 min
+- **Started:** 2026-03-05T00:00:00Z
+- **Completed:** 2026-03-05T00:03:04Z
+- **Tasks:** 3
+- **Files modified:** 3 (1 created, 2 modified)
+
+## Accomplishments
+- Created useDebounceCallback hook solving stale closure problem with debounced callbacks
+- Replaced triple setTimeout pattern (1s, 1.4s, 6s) with single 1.5s debounced call
+- Fixed trackChanges debounce timer resetting on dependency changes
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Create useDebounceCallback hook** - `1a42be980` (feat)
+2. **Task 2: Consolidate track sync to single debounced call** - `de5b331e0` (feat)
+3. **Task 3: Fix trackChanges debounce in useSessionModel** - `f0ddd9d7c` (feat)
+
+## Files Created/Modified
+- `jam-ui/src/hooks/useDebounceCallback.js` - Reusable ref-based debounce hook that solves stale closure problem
+- `jam-ui/src/components/client/JKSessionScreen.js` - Replaced triple track sync timers with single debounced call
+- `jam-ui/src/hooks/useSessionModel.js` - Updated trackChanges to use useDebounceCallback for stable timer
+
+## Decisions Made
+
+1. **1.5s debounce delay for track sync**
+   - Legacy used 1s, 1.4s, and 6s delays
+   - First two calls (1s, 1.4s) were redundant
+   - Single 1.5s delay covers mixer initialization window
+   - Can increase if slow network issues arise
+
+2. **useDebounceCallback pattern with refs**
+   - useRef stores latest callback (always current)
+   - useMemo creates debounce once with [delay] deps only
+   - Callback reads fresh closure values via ref
+   - Timer stable across state changes
+
+3. **Remove lodash debounce import from useSessionModel**
+   - trackChanges was only usage in file
+   - useDebounceCallback handles debouncing internally
+   - Cleaner dependency graph
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+
+None - implementation proceeded smoothly with ESLint auto-fix handling pre-existing formatting issues.
+
+## User Setup Required
+
+None - no external service configuration required.
+
+## Next Phase Readiness
+
+**Ready for performance testing:**
+- Track sync now fires once per session join (not 3 times)
+- Debounce timers stable across state changes
+- All changes backward-compatible with existing session join flow
+- Ready for performance measurement and validation
+
+**Blockers/concerns:**
+- None
+
+**Testing recommendations for next phase:**
+- Verify track sync fires exactly once after session join
+- Measure API call count reduction (expect 66% reduction from 3 to 1)
+- Verify trackChanges debounce timer doesn't reset during rapid state updates
+- Test session join on slow networks (may need to increase 1.5s delay)
+
+---
+*Phase: 32-state-update-optimization*
+*Completed: 2026-03-05*