feat(ai): implement intelligent auto-tagging system

- Added multi-provider AI infrastructure (OpenAI/Ollama)
- Implemented real-time tag suggestions with debounced analysis
- Created AI diagnostics and database maintenance tools in Settings
- Added automated garbage collection for orphan labels
- Refined UX with deterministic color hashing and interactive ghost tags

_bmad-output/implementation-artifacts/2-1-infrastructure-ia-abstraction-provider.md

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+# Story 2.1: Infrastructure IA & Abstraction Provider
+
+Status: done
+
+## Story
+
+As an administrator,
+I want to configure my AI provider (OpenAI or Ollama) centrally,
+so that the application can use artificial intelligence securely.
+
+## Acceptance Criteria
+
+1. **Given** an `AIProvider` interface and the `Vercel AI SDK` installed.
+2. **When** I provide my API key or Ollama instance URL in environment variables.
+3. **Then** the system initializes the appropriate driver.
+4. **And** no API keys are exposed to the client-side.
+
+## Tasks / Subtasks
+
+- [x] Installation du Vercel AI SDK (AC: 1)
+  - [x] `npm install ai @ai-sdk/openai ollama-ai-provider`
+- [x] Création de l'interface d'abstraction `AIProvider` (AC: 1, 3)
+  - [x] Définir les méthodes standard (ex: `generateTags(content: string)`, `getEmbeddings(text: string)`)
+- [x] Implémentation des drivers (AC: 3)
+  - [x] `OpenAIProvider` utilisant le SDK officiel
+  - [x] `OllamaProvider` pour le support local
+- [x] Configuration via variables d'environnement (AC: 2, 4)
+  - [x] Gérer `AI_PROVIDER`, `OPENAI_API_KEY`, `OLLAMA_BASE_URL` dans `.env`
+  - [x] Créer une factory pour initialiser le bon provider au démarrage du serveur
+- [x] Test de connexion (AC: 3)
+  - [x] Créer un endpoint de santé/test pour vérifier la communication avec le provider configuré
+
+## Senior Developer Review (AI)
+- **Review Date:** 2026-01-08
+- **Status:** Approved with auto-fixes
+- **Fixes Applied:**
+  - Switched to `generateObject` with Zod for robust parsing.
+  - Added strict error handling and timeouts.
+  - Improved prompts and system messages.
+
+## Dev Agent Record
+
+### Agent Model Used
+BMad Master (Gemini 2.0 Flash)
+
+### Debug Log References
+- Infrastructure created in keep-notes/lib/ai
+- Packages: ai, @ai-sdk/openai, ollama-ai-provider
+- Test endpoint: /api/ai/test
+
+### Completion Notes List
+- [x] Abstraction interface defined
+- [x] Factory pattern implemented
+- [x] OpenAI and Ollama drivers ready
+- [x] API test route created
+
+### File List
+- keep-notes/lib/ai/types.ts
+- keep-notes/lib/ai/factory.ts
+- keep-notes/lib/ai/providers/openai.ts
+- keep-notes/lib/ai/providers/ollama.ts
+- keep-notes/app/api/ai/test/route.ts
+
+Status: review
+