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/app/api/admin/randomize-labels/route.ts

@@ -0,0 +1,31 @@
+import { NextResponse } from 'next/server';
+import prisma from '@/lib/prisma';
+import { LABEL_COLORS } from '@/lib/types';
+
+export const dynamic = 'force-dynamic';
+
+export async function GET() {
+  try {
+    const labels = await prisma.label.findMany();
+    const colors = Object.keys(LABEL_COLORS).filter(c => c !== 'gray'); // Exclude gray to force colors
+    
+    const updates = labels.map((label: any) => {
+      const randomColor = colors[Math.floor(Math.random() * colors.length)];
+      return prisma.label.update({
+        where: { id: label.id },
+        data: { color: randomColor }
+      });
+    });
+
+    await prisma.$transaction(updates);
+
+    return NextResponse.json({
+      success: true,
+      updated: updates.length,
+      message: "All labels have been assigned a random non-gray color."
+    });
+
+  } catch (error) {
+    return NextResponse.json({ error: String(error) }, { status: 500 });
+  }
+}