docs: create multi-provider support roadmap (6 phases)

Enable Replicate and fal.ai alongside existing Gemini integration

Phases:
1. Provider Infrastructure: API key storage and settings UI
2. Model Discovery: Dynamic model fetching from provider APIs
3. Generate Node Refactor: Multi-model support in generic Generate node
4. Model Search Dialog: Floating icons and searchable model browser
5. Image URL Server: Local endpoint for URL-based providers
6. Video & Polish: Video playback and parameter customization

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

.planning/ROADMAP.md

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+# Roadmap: Node Banana Multi-Provider Support
+
+## Overview
+
+Transform Node Banana from a Gemini-only image generator into a multi-provider platform supporting Replicate and fal.ai. The journey builds provider infrastructure first, then adds dynamic model discovery, refactors the generate node for flexibility, creates a searchable model browser, adds local image serving for URL-based providers, and finishes with video support and polish.
+
+## Domain Expertise
+
+None
+
+## Phases
+
+**Phase Numbering:**
+- Integer phases (1, 2, 3): Planned milestone work
+- Decimal phases (2.1, 2.2): Urgent insertions (marked with INSERTED)
+
+- [ ] **Phase 1: Provider Infrastructure** - API key storage and provider settings UI
+- [ ] **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
+- [ ] **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
+
+## Phase Details
+
+### Phase 1: Provider Infrastructure
+**Goal**: Users can configure Replicate and fal.ai API keys in settings, with keys securely stored
+**Depends on**: Nothing (first phase)
+**Research**: Unlikely (internal UI patterns, Zustand state management)
+**Plans**: TBD
+
+Plans:
+- [ ] 01-01: Provider settings UI in ProjectSetupModal
+- [ ] 01-02: Provider abstraction layer and types
+
+### Phase 2: Model Discovery
+**Goal**: App can fetch and cache available models from enabled providers at runtime
+**Depends on**: Phase 1
+**Research**: Likely (external APIs)
+**Research topics**: Replicate model listing API endpoints, fal.ai model discovery endpoints, response schemas and pagination
+**Plans**: TBD
+
+Plans:
+- [ ] 02-01: Replicate model fetching API route
+- [ ] 02-02: fal.ai model fetching API route
+- [ ] 02-03: Model caching and unified model interface
+
+### Phase 3: Generate Node Refactor
+**Goal**: NanoBanana node becomes generic Generate node supporting any provider's model
+**Depends on**: Phase 2
+**Research**: Unlikely (internal refactoring using existing patterns)
+**Plans**: TBD
+
+Plans:
+- [ ] 03-01: Rename NanoBanana to Generate, add model selector
+- [ ] 03-02: Provider-specific execution in generate API route
+- [ ] 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
+**Depends on**: Phase 3
+**Research**: Unlikely (internal UI using React patterns)
+**Plans**: TBD
+
+Plans:
+- [ ] 04-01: Floating action bar with provider icons
+- [ ] 04-02: Model search dialog with filtering and selection
+
+### Phase 5: Image URL Server
+**Goal**: Local API endpoint serves workflow images as URLs for providers requiring URL inputs
+**Depends on**: Phase 3
+**Research**: Unlikely (Next.js API routes, existing patterns)
+**Plans**: TBD
+
+Plans:
+- [ ] 05-01: Image serving endpoint and URL generation
+- [ ] 05-02: Integration with generate node for URL-based providers
+
+### Phase 6: Video & Polish
+**Goal**: Video outputs play inline, custom parameters work, edge cases handled
+**Depends on**: Phase 5
+**Research**: Likely (video handling)
+**Research topics**: HTML5 video element for base64/blob URLs, provider response formats for video content
+**Plans**: TBD
+
+Plans:
+- [ ] 06-01: Video playback in output node
+- [ ] 06-02: Custom model parameters from provider schemas
+- [ ] 06-03: Edge case handling and final polish
+
+## Progress
+
+**Execution Order:**
+Phases execute in numeric order: 1 → 2 → 3 → 4 → 5 → 6
+
+| Phase | Plans Complete | Status | Completed |
+|-------|----------------|--------|-----------|
+| 1. Provider Infrastructure | 0/2 | Not started | - |
+| 2. Model Discovery | 0/3 | Not started | - |
+| 3. Generate Node Refactor | 0/3 | Not started | - |
+| 4. Model Search Dialog | 0/2 | Not started | - |
+| 5. Image URL Server | 0/2 | Not started | - |
+| 6. Video & Polish | 0/3 | Not started | - |

.planning/STATE.md

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+# Project State
+
+## Project Reference
+
+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 1 — Provider Infrastructure
+
+## Current Position
+
+Phase: 1 of 6 (Provider Infrastructure)
+Plan: Not started
+Status: Ready to plan
+Last activity: 2026-01-09 — Project initialized
+
+Progress: ░░░░░░░░░░ 0%
+
+## Performance Metrics
+
+**Velocity:**
+- Total plans completed: 0
+- Average duration: —
+- Total execution time: 0 hours
+
+**By Phase:**
+
+| Phase | Plans | Total | Avg/Plan |
+|-------|-------|-------|----------|
+| — | — | — | — |
+
+**Recent Trend:**
+- Last 5 plans: —
+- Trend: —
+
+## Accumulated Context
+
+### Decisions
+
+Decisions are logged in PROJECT.md Key Decisions table.
+Recent decisions affecting current work:
+
+(None yet)
+
+### Deferred Issues
+
+None yet.
+
+### Blockers/Concerns
+
+None yet.
+
+## Session Continuity
+
+Last session: 2026-01-09
+Stopped at: Project initialization complete
+Resume file: None