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/lib/utils.ts

@@ -1,6 +1,21 @@
 import { clsx, type ClassValue } from "clsx"
 import { twMerge } from "tailwind-merge"
+import { LABEL_COLORS, LabelColorName } from "./types"
 
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs))
 }
+
+export function getHashColor(name: string): LabelColorName {
+  let hash = 0;
+  for (let i = 0; i < name.length; i++) {
+    hash = name.charCodeAt(i) + ((hash << 5) - hash);
+  }
+  
+  const colors = Object.keys(LABEL_COLORS) as LabelColorName[];
+  // Skip 'gray' for colorful tags
+  const colorfulColors = colors.filter(c => c !== 'gray');
+  const colorIndex = Math.abs(hash) % colorfulColors.length;
+  
+  return colorfulColors[colorIndex];
+}