docs(01-02): complete provider abstraction plan

Add summary documenting provider abstraction implementation:
- Provider interfaces in src/lib/providers/types.ts
- Provider registry in src/lib/providers/index.ts
- Phase 1 complete, ready for Phase 2: Model Discovery

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

.planning/phases/01-provider-infrastructure/01-02-SUMMARY.md

@@ -0,0 +1,95 @@
+---
+phase: 01-provider-infrastructure
+plan: 02
+subsystem: api
+tags: [providers, abstraction, typescript, interfaces]
+
+# Dependency graph
+requires:
+  - phase: 01-01
+    provides: ProviderType, ProviderConfig, ProviderSettings types
+provides:
+  - ProviderModel interface for normalized model metadata
+  - ModelCapability union type for model capabilities
+  - GenerationInput/GenerationOutput interfaces for unified I/O
+  - ProviderInterface contract for provider implementations
+  - Provider registry with register/get functions
+affects: [02-model-discovery, multi-provider generation]
+
+# Tech tracking
+tech-stack:
+  added: []
+  patterns: [provider abstraction pattern, self-registering modules]
+
+key-files:
+  created:
+    - src/lib/providers/types.ts
+    - src/lib/providers/index.ts
+  modified: []
+
+key-decisions:
+  - "Provider registry uses self-registration pattern via registerProvider()"
+  - "Gemini remains special-cased in /api/generate for now, not yet migrated"
+
+patterns-established:
+  - "Provider types in src/lib/providers/types.ts"
+  - "Provider registry in src/lib/providers/index.ts"
+  - "Providers self-register when their modules are imported"
+
+issues-created: []
+
+# Metrics
+duration: 2min
+completed: 2026-01-09
+---
+
+# Phase 01-02: Provider Abstraction Summary
+
+**Provider abstraction interfaces and registry for unified access to Gemini, Replicate, and fal.ai**
+
+## Performance
+
+- **Duration:** 2 min
+- **Started:** 2026-01-09T02:35:42Z
+- **Completed:** 2026-01-09T02:38:05Z
+- **Tasks:** 2
+- **Files created:** 2
+
+## Accomplishments
+- Created provider abstraction interfaces defining how providers expose model discovery and generation
+- Established ProviderInterface contract that all providers will implement
+- Built provider registry with self-registration pattern for dynamic provider discovery
+- Phase 1 complete - ready for Phase 2: Model Discovery
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: Create provider abstraction interfaces** - `8b49db4` (feat)
+2. **Task 2: Create provider registry and factory** - `c8618ab` (feat)
+
+## Files Created/Modified
+- `src/lib/providers/types.ts` - Provider abstraction interfaces (ProviderModel, ProviderInterface, GenerationInput/Output, ModelCapability)
+- `src/lib/providers/index.ts` - Provider registry with registerProvider(), getProvider(), getConfiguredProviders(), getAllProviders()
+
+## Decisions Made
+- Used self-registration pattern where provider modules call registerProvider() on import
+- Gemini provider remains special-cased in /api/generate route; may migrate in future phase
+- Types exported from both files for convenient imports via "@/lib/providers"
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+- `npm run lint` has pre-existing configuration issue (missing eslint.config.js for ESLint v9). This is not related to this plan's changes. Build passes successfully.
+
+## Next Phase Readiness
+- Provider abstraction layer complete with all interfaces defined
+- Registry ready to accept provider registrations from Phase 2
+- Phase 1 (Provider Infrastructure) complete
+- Ready for Phase 2: Model Discovery (Replicate and fal.ai implementations)
+
+---
+*Phase: 01-provider-infrastructure*
+*Completed: 2026-01-09*