docs(03-03): complete backward compatibility plan

Tasks completed: 3/3
- Add workflow migration logic for legacy nodes
- Update executeWorkflow for multi-provider dispatch
- Handle legacy data in GenerateImageNode UI

SUMMARY: .planning/phases/03-generate-node-refactor/03-03-SUMMARY.md

.planning/ROADMAP.md

@@ -16,7 +16,7 @@ None
 
 - [x] **Phase 1: Provider Infrastructure** - API key storage and provider settings UI ✓
 - [x] **Phase 2: Model Discovery** - Dynamic model fetching from Replicate/fal.ai APIs ✓
-- [ ] **Phase 3: Generate Node Refactor** - Rename NanoBanana to generic Generate with multi-model support
+- [x] **Phase 3: Generate Node Refactor** - Rename NanoBanana to generic Generate with multi-model support ✓
 - [ ] **Phase 4: Model Search Dialog** - Floating action bar icons and searchable model browser
 - [ ] **Phase 5: Image URL Server** - Local endpoint serving images as URLs for providers
 - [ ] **Phase 6: Video & Polish** - Video playback, parameter customization, edge cases
@@ -54,7 +54,7 @@ Plans:
 Plans:
 - [x] 03-01: Rename NanoBanana to GenerateImage, add model selector (image models only)
 - [x] 03-02: Provider-specific execution in generate API route
-- [ ] 03-03: Backward compatibility for existing workflows
+- [x] 03-03: Backward compatibility for existing workflows
 
 ### Phase 4: Model Search Dialog
 **Goal**: Users can browse models via floating action bar icons and searchable dialog
@@ -98,7 +98,7 @@ Phases execute in numeric order: 1 → 2 → 3 → 4 → 5 → 6
 |-------|----------------|--------|-----------|
 | 1. Provider Infrastructure | 2/2 | Complete | 2026-01-09 |
 | 2. Model Discovery | 3/3 | Complete | 2026-01-09 |
-| 3. Generate Node Refactor | 2/3 | In progress | - |
+| 3. Generate Node Refactor | 3/3 | Complete | 2026-01-09 |
 | 4. Model Search Dialog | 0/2 | Not started | - |
 | 5. Image URL Server | 0/2 | Not started | - |
 | 6. Video & Polish | 0/4 | Not started | - |

.planning/STATE.md

@@ -5,23 +5,23 @@
 See: .planning/PROJECT.md (updated 2026-01-09)
 
 **Core value:** Provider infrastructure that dynamically discovers models from external APIs, enabling users to access hundreds of image/video generation models without hardcoding schemas.
-**Current focus:** Phase 3 - Generate Node Refactor
+**Current focus:** Phase 4 - Model Search Dialog
 
 ## Current Position
 
-Phase: 3 of 6 (Generate Node Refactor)
-Plan: 2 of 3 in current phase
-Status: In progress
-Last activity: 2026-01-09 - Completed 03-02-PLAN.md (Provider-specific execution)
+Phase: 3 of 6 (Generate Node Refactor) - COMPLETE
+Plan: 3 of 3 in current phase
+Status: Phase complete
+Last activity: 2026-01-09 - Completed 03-03-PLAN.md (Backward compatibility)
 
-Progress: [==========================================] 47% (7/15 plans)
+Progress: [======================================================] 53% (8/15 plans)
 
 ## Performance Metrics
 
 **Velocity:**
-- Total plans completed: 7
-- Average duration: 5.3 min
-- Total execution time: 0.62 hours
+- Total plans completed: 8
+- Average duration: 4.9 min
+- Total execution time: 0.67 hours
 
 **By Phase:**
 
@@ -29,11 +29,11 @@ Progress: [==========================================] 47% (7/15 plans)
 |-------|-------|-------|----------|
 | 1. Provider Infrastructure | 2/2 | 14 min | 7 min |
 | 2. Model Discovery | 3/3 | 14 min | 4.7 min |
-| 3. Generate Node Refactor | 2/3 | 10 min | 5 min |
+| 3. Generate Node Refactor | 3/3 | 13 min | 4.3 min |
 
 **Recent Trend:**
-- Last 5 plans: 5 min, 5 min, 5 min, 5 min
-- Trend: stable
+- Last 5 plans: 5 min, 5 min, 5 min, 3 min
+- Trend: improving
 
 ## Accumulated Context
 
@@ -60,6 +60,7 @@ Recent decisions affecting current work:
 - Server-side provider execution in API route (not client-side)
 - Header-based API key passing: X-Replicate-API-Key, X-Fal-API-Key
 - fal.ai sync API (fal.run) instead of queue-based async
+- Dual migration approach: loadWorkflow migrates + UI effect for runtime
 
 ### Deferred Issues
 
@@ -72,6 +73,6 @@ None.
 ## Session Continuity
 
 Last session: 2026-01-09
-Stopped at: Completed 03-02-PLAN.md (Provider-specific execution)
+Stopped at: Completed 03-03-PLAN.md (Backward compatibility)
 Resume file: None
-Next action: Execute 03-03-PLAN.md (Backward compatibility for existing workflows)
+Next action: Plan Phase 4 (Model Search Dialog)

.planning/phases/03-generate-node-refactor/03-03-SUMMARY.md

@@ -0,0 +1,100 @@
+---
+phase: 03-generate-node-refactor
+plan: 03
+subsystem: compatibility
+tags: [migration, backward-compatibility, legacy-workflows, multi-provider]
+
+# Dependency graph
+requires:
+  - phase: 03-01
+    provides: GenerateImageNode with SelectedModel type
+  - phase: 03-02
+    provides: Multi-provider dispatch in /api/generate route
+provides:
+  - Workflow migration logic for legacy nanoBanana nodes
+  - Multi-provider execution with API key headers in workflowStore
+  - Legacy data handling in GenerateImageNode UI
+affects: [04-model-search-dialog]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns:
+    - Workflow migration on load in loadWorkflow()
+    - UI-side migration effect for runtime compatibility
+
+key-files:
+  created: []
+  modified:
+    - src/store/workflowStore.ts
+    - src/components/nodes/GenerateImageNode.tsx
+
+key-decisions:
+  - "Dual migration: loadWorkflow migrates data, UI effect ensures runtime compatibility"
+  - "API key headers passed from providerSettings state in executeWorkflow/regenerateNode"
+  - "selectedModel included in request payload for provider routing"
+
+patterns-established:
+  - "Migration pattern: check for old data format, derive new format, update node"
+  - "Provider-agnostic logging: use provider variable in log messages"
+
+issues-created: []
+
+# Metrics
+duration: 3 min
+completed: 2026-01-09
+---
+
+# Phase 3 Plan 3: Backward Compatibility Summary
+
+**Workflow migration logic and multi-provider execution in workflowStore ensuring legacy Gemini workflows load and execute unchanged**
+
+## Performance
+
+- **Duration:** 3 min
+- **Started:** 2026-01-09T07:43:18Z
+- **Completed:** 2026-01-09T07:46:38Z
+- **Tasks:** 3
+- **Files modified:** 2
+
+## Accomplishments
+- Workflow migration on load: legacy nanoBanana nodes without selectedModel auto-populated
+- Multi-provider execution: API key headers and selectedModel passed in requests
+- UI-side migration: GenerateImageNode derives selectedModel on mount for runtime compatibility
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Add workflow migration logic** - `2811e62` (feat)
+2. **Task 2: Update executeWorkflow for multi-provider** - `da326c9` (feat)
+3. **Task 3: Handle legacy data in UI** - `88b8962` (feat)
+
+**Plan metadata:** `0e1f163` (docs: complete plan)
+
+## Files Created/Modified
+- `src/store/workflowStore.ts` - Migration in loadWorkflow, API key headers in executeWorkflow/regenerateNode
+- `src/components/nodes/GenerateImageNode.tsx` - useEffect for UI-side migration
+
+## Decisions Made
+- Dual migration approach: server-side on workflow load + client-side for runtime
+- API key headers (X-Replicate-API-Key, X-Fal-API-Key) for external providers
+- selectedModel included in request body for provider dispatch
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+
+None
+
+## Next Phase Readiness
+- Phase 3 (Generate Node Refactor) complete
+- All legacy workflows load with auto-populated selectedModel
+- Multi-provider execution working for Gemini, Replicate, and fal.ai
+- Ready for Phase 4: Model Search Dialog
+
+---
+*Phase: 03-generate-node-refactor*
+*Completed: 2026-01-09*