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>

scripts/migrate-to-notebooks.ts

@@ -15,7 +15,7 @@
  *   npx tsx scripts/rollback-notebooks.ts
  */
 
-import { prisma } from '../keep-notes/lib/prisma'
+import { prisma } from '../memento-note/lib/prisma'
 
 interface MigrationStats {
   usersProcessed: number

scripts/rollback-notebooks.ts

@@ -16,7 +16,7 @@
  *   npx tsx scripts/rollback-notebooks.ts --confirm
  */
 
-import { prisma } from '../keep-notes/lib/prisma'
+import { prisma } from '../memento-note/lib/prisma'
 
 interface RollbackStats {
   notebooksDeleted: number

scripts/verify-migration.js

@@ -1,4 +1,4 @@
-const { PrismaClient } = require('../keep-notes/prisma/client-generated');
+const { PrismaClient } = require('../memento-note/prisma/client-generated');
 const prisma = new PrismaClient();
 
 (async () => {