docs(02-01): complete flexible sets plan 01 — summary and state update

- 02-01-SUMMARY.md: dynamic setList refactor, add-set modal, delete-set with last-set guard
- STATE.md: advance to phase 2 plan 2, record decisions, update metrics and session

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/STATE.md

@@ -9,12 +9,12 @@ See: .planning/PROJECT.md (updated 2026-02-15)
 
 ## Current Position
 
-Phase: 1 of 3 (Input UX)
-Plan: 3 of 3 in current phase
-Status: Phase 1 complete (all 3 plans done: 01, 02, 03)
-Last activity: 2026-02-16 — Completed 01-02 (stepper integration into WorkoutPage)
+Phase: 2 of 3 (Flexible Sets)
+Plan: 1 of 2 in current phase (02-01 complete)
+Status: Phase 2 in progress — plan 02-01 done, 02-02 pending
+Last activity: 2026-02-21 — Completed 02-01 (ExerciseCard dynamic setList, add-set modal, delete-set)
 
-Progress: [████░░░░░░] 40%
+Progress: [█████░░░░░] 50%
 
 ## Performance Metrics
 
@@ -28,9 +28,10 @@ Progress: [████░░░░░░] 40%
 | Phase | Plans | Total | Avg/Plan |
 |-------|-------|-------|----------|
 | 01-input-ux | 3/3 | ~4 min | ~1.3 min |
+| 02-flexible-sets | 1/2 | ~8 min | ~8 min |
 
 **Recent Trend:**
-- Last 5 plans: 01-01 (1 min), 01-03 (2 min), 01-02 (1 min)
+- Last 5 plans: 01-01 (1 min), 01-03 (2 min), 01-02 (1 min), 02-01 (8 min)
 - Trend: fast
 
 *Updated after each plan completion*
@@ -49,6 +50,11 @@ Progress: [████░░░░░░] 40%
 - All App.css interactive elements have min-height: 44px; global input font-size: 16px prevents iOS auto-zoom across all form fields
 - handleInputChange already accepts plain string values — WeightInput/RepsInput onChange passes string directly, no signature changes needed
 - flex-start alignment on .set-row and .set-inputs accommodates taller stepper containers
+- setList uses array index (not set_number key) — set_number derived as idx+1 when calling onLogSet
+- Dropset weight drops: 80% then 60% of base weight, each rounded to nearest 2.5kg per app progression convention
+- Last-set guard: handleDeleteSet returns early if setList.length <= 1, delete button also disabled in DOM
+- progress-badge and all-done class reference setList.length instead of exercise.sets — badge reflects actual set count
+- onDeleteSet prop is optional stub in ExerciseCard — backend wiring deferred to plan 02-02
 
 ### Pending Todos
 
@@ -60,6 +66,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-02-16
-Stopped at: Completed 01-02-PLAN.md (stepper integration into ExerciseCard set rows)
+Last session: 2026-02-21
+Stopped at: Completed 02-01-PLAN.md (ExerciseCard dynamic setList, add-set modal, delete-set button)
 Resume file: None