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/actions/register.ts

@@ -0,0 +1,63 @@
+'use server';
+
+import bcrypt from 'bcryptjs';
+import prisma from '@/lib/prisma';
+import { z } from 'zod';
+import { redirect } from 'next/navigation';
+import { getSystemConfig } from '@/lib/config';
+
+const RegisterSchema = z.object({
+  email: z.string().email(),
+  password: z.string().min(6),
+  name: z.string().min(2),
+});
+
+export async function register(prevState: string | undefined, formData: FormData) {
+  // Check if registration is allowed
+  const config = await getSystemConfig();
+  const allowRegister = config.ALLOW_REGISTRATION !== 'false' && process.env.ALLOW_REGISTRATION !== 'false';
+
+  if (!allowRegister) {
+    return 'Registration is currently disabled by the administrator.';
+  }
+
+  const validatedFields = RegisterSchema.safeParse({
+    email: formData.get('email'),
+    password: formData.get('password'),
+    name: formData.get('name'),
+  });
+
+  if (!validatedFields.success) {
+    return 'Invalid fields. Failed to register.';
+  }
+
+  const { email, password, name } = validatedFields.data;
+
+  try {
+    const existingUser = await prisma.user.findUnique({ where: { email: email.toLowerCase() } });
+    if (existingUser) {
+      return 'User already exists.';
+    }
+
+    const hashedPassword = await bcrypt.hash(password, 10);
+
+    await prisma.user.create({
+      data: {
+        email: email.toLowerCase(),
+        password: hashedPassword,
+        name,
+      },
+    });
+    
+    // Attempt to sign in immediately after registration
+    // We cannot import signIn here directly if it causes circular deps or issues, 
+    // but usually it works. If not, redirecting to login is fine.
+    // Let's stick to redirecting to login but with a clear success message?
+    // Or better: lowercase the email to fix the potential bug.
+  } catch (error) {
+    console.error('Registration Error:', error);
+    return 'Database Error: Failed to create user.';
+  }
+
+  redirect('/login');
+}