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>

mcp-server/Dockerfile

@@ -1,5 +1,5 @@
 # Base image
-FROM node:20-alpine
+FROM node:22-alpine
 
 # Install dependencies
 WORKDIR /app
@@ -16,15 +16,13 @@ RUN npm ci --only=production
 # Copy application code
 COPY . .
 
-# Copy Prisma schema and client
+# Copy Prisma schema and generate client
 COPY prisma ./prisma
+RUN npx prisma generate
 
 # Create non-root user
 RUN addgroup -g 1001 -S mcp && \
-    adduser -u 1001 -S mcp -G mcp
-
-# Create database directory
-RUN mkdir -p /app/db && \
+    adduser -u 1001 -S mcp -G mcp && \
     chown -R mcp:mcp /app
 
 USER mcp