feat: rename keep-notes to memento-note, migrate to PostgreSQL, fix MCP bugs

- Rename directory keep-notes -> memento-note with all code references
- Prisma: SQLite -> PostgreSQL (both app and MCP server schemas)
- Sync MCP schema with main app (add missing fields, relations, indexes)
- Delete 17 SQLite migrations (clean slate for PostgreSQL)
- Remove SQLite dependencies (@libsql/client, better-sqlite3, etc.)
- Fix MCP server: hardcoded Windows DB paths -> DATABASE_URL env var
- Fix MCP server: .dockerignore excluded index-sse.js (SSE mode broken)
- MCP Dockerfile: node:20 -> node:22
- Docker Compose: add postgres service, remove SQLite volume
- Generate favicon.ico, icon-192.png, icon-512.png, apple-icon.png
- Update layout.tsx icons and manifest.json for PNG icons
- Update all .env files for PostgreSQL
- Rewrite README.md with updated sections
- Remove mcp-server/node_modules and prisma/client-generated from git tracking

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

memento-note/lib/label-storage.ts

@@ -0,0 +1,57 @@
+import { LabelColorName } from './types'
+
+const STORAGE_KEY = 'memento-label-colors'
+
+// Store label colors in localStorage
+export function getLabelColor(label: string): LabelColorName {
+  if (typeof window === 'undefined') return 'gray'
+  
+  try {
+    const stored = localStorage.getItem(STORAGE_KEY)
+    if (!stored) return 'gray'
+    
+    const colors = JSON.parse(stored) as Record<string, LabelColorName>
+    return colors[label] || 'gray'
+  } catch {
+    return 'gray'
+  }
+}
+
+export function setLabelColor(label: string, color: LabelColorName) {
+  if (typeof window === 'undefined') return
+  
+  try {
+    const stored = localStorage.getItem(STORAGE_KEY)
+    const colors = stored ? JSON.parse(stored) as Record<string, LabelColorName> : {}
+    colors[label] = color
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(colors))
+  } catch (error) {
+    console.error('Failed to save label color:', error)
+  }
+}
+
+export function getAllLabelColors(): Record<string, LabelColorName> {
+  if (typeof window === 'undefined') return {}
+  
+  try {
+    const stored = localStorage.getItem(STORAGE_KEY)
+    return stored ? JSON.parse(stored) : {}
+  } catch {
+    return {}
+  }
+}
+
+export function deleteLabelColor(label: string) {
+  if (typeof window === 'undefined') return
+  
+  try {
+    const stored = localStorage.getItem(STORAGE_KEY)
+    if (!stored) return
+    
+    const colors = JSON.parse(stored) as Record<string, LabelColorName>
+    delete colors[label]
+    localStorage.setItem(STORAGE_KEY, JSON.stringify(colors))
+  } catch (error) {
+    console.error('Failed to delete label color:', error)
+  }
+}