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/labels/route.ts

@@ -0,0 +1,129 @@
+import { NextRequest, NextResponse } from 'next/server'
+import prisma from '@/lib/prisma'
+import { auth } from '@/auth'
+
+const COLORS = ['red', 'orange', 'yellow', 'green', 'teal', 'blue', 'purple', 'pink', 'gray'];
+
+// GET /api/labels - Get all labels (supports optional notebookId filter)
+export async function GET(request: NextRequest) {
+  const session = await auth();
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  try {
+    const searchParams = request.nextUrl.searchParams
+    const notebookId = searchParams.get('notebookId')
+
+    // Build where clause
+    const where: any = {}
+
+    if (notebookId === 'null' || notebookId === '') {
+      // Get labels without a notebook (backward compatibility)
+      where.notebookId = null
+    } else if (notebookId) {
+      // Get labels for a specific notebook
+      where.notebookId = notebookId
+    } else {
+      // Get all labels for the user (both old and new system)
+      where.OR = [
+        { notebookId: { not: null } },
+        { userId: session.user.id }
+      ]
+    }
+
+    const labels = await prisma.label.findMany({
+      where,
+      include: {
+        notebook: {
+          select: { id: true, name: true }
+        }
+      },
+      orderBy: { name: 'asc' }
+    })
+
+    return NextResponse.json({
+      success: true,
+      data: labels
+    })
+  } catch (error) {
+    return NextResponse.json(
+      { success: false, error: 'Failed to fetch labels' },
+      { status: 500 }
+    )
+  }
+}
+
+// POST /api/labels - Create a new label
+export async function POST(request: NextRequest) {
+  const session = await auth();
+  if (!session?.user?.id) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+
+  try {
+    const body = await request.json()
+    const { name, color, notebookId } = body
+
+    if (!name || typeof name !== 'string') {
+      return NextResponse.json(
+        { success: false, error: 'Label name is required' },
+        { status: 400 }
+      )
+    }
+
+    if (!notebookId || typeof notebookId !== 'string') {
+      return NextResponse.json(
+        { success: false, error: 'notebookId is required' },
+        { status: 400 }
+      )
+    }
+
+    // Verify notebook ownership
+    const notebook = await prisma.notebook.findUnique({
+      where: { id: notebookId },
+      select: { userId: true }
+    })
+
+    if (!notebook || notebook.userId !== session.user.id) {
+      return NextResponse.json(
+        { success: false, error: 'Notebook not found or unauthorized' },
+        { status: 403 }
+      )
+    }
+
+    // Check if label already exists in this notebook
+    const existing = await prisma.label.findFirst({
+      where: {
+        name: name.trim(),
+        notebookId: notebookId
+      }
+    })
+
+    if (existing) {
+      return NextResponse.json(
+        { success: false, error: 'Label already exists in this notebook' },
+        { status: 409 }
+      )
+    }
+
+    const label = await prisma.label.create({
+      data: {
+        name: name.trim(),
+        color: color || COLORS[Math.floor(Math.random() * COLORS.length)],
+        notebookId: notebookId,
+        userId: session.user.id // Keep for backward compatibility
+      }
+    })
+
+    return NextResponse.json({
+      success: true,
+      data: label
+    }, { status: 201 })
+  } catch (error) {
+    return NextResponse.json(
+      { success: false, error: 'Failed to create label' },
+      { status: 500 }
+    )
+  }
+}