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

keep-notes/hooks/use-auto-tagging.ts

@@ -0,0 +1,61 @@
+import { useState, useEffect } from 'react';
+import { useDebounce } from './use-debounce';
+import { TagSuggestion } from '@/lib/ai/types';
+
+interface UseAutoTaggingProps {
+  content: string;
+  enabled?: boolean;
+}
+
+export function useAutoTagging({ content, enabled = true }: UseAutoTaggingProps) {
+  const [suggestions, setSuggestions] = useState<TagSuggestion[]>([]);
+  const [isAnalyzing, setIsAnalyzing] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  // Debounce le contenu de 1.5s
+  const debouncedContent = useDebounce(content, 1500);
+
+  useEffect(() => {
+    // console.log('AutoTagging Effect:', { enabled, contentLength: debouncedContent?.length });
+    if (!enabled || !debouncedContent || debouncedContent.length < 10) {
+      setSuggestions([]);
+      return;
+    }
+
+    const analyzeContent = async () => {
+      console.log('🚀 Triggering AI analysis for:', debouncedContent.substring(0, 20) + '...');
+      setIsAnalyzing(true);
+      setError(null);
+
+      try {
+        const response = await fetch('/api/ai/tags', {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ content: debouncedContent }),
+        });
+
+        if (!response.ok) {
+          throw new Error('Erreur lors de l\'analyse');
+        }
+
+        const data = await response.json();
+        console.log('✅ AI Response:', data);
+        setSuggestions(data.tags || []);
+      } catch (err) {
+        console.error('❌ Auto-tagging error:', err);
+        setError('Impossible de générer des suggestions');
+      } finally {
+        setIsAnalyzing(false);
+      }
+    };
+
+    analyzeContent();
+  }, [debouncedContent, enabled]);
+
+  return {
+    suggestions,
+    isAnalyzing,
+    error,
+    clearSuggestions: () => setSuggestions([]),
+  };
+}

keep-notes/hooks/use-debounce.ts

@@ -0,0 +1,17 @@
+import { useEffect, useState } from 'react';
+
+export function useDebounce<T>(value: T, delay: number): T {
+  const [debouncedValue, setDebouncedValue] = useState<T>(value);
+
+  useEffect(() => {
+    const timer = setTimeout(() => {
+      setDebouncedValue(value);
+    }, delay);
+
+    return () => {
+      clearTimeout(timer);
+    };
+  }, [value, delay]);
+
+  return debouncedValue;
+}