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/ai/suggest-notebook/route.ts

@@ -0,0 +1,46 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { auth } from '@/auth'
+import { notebookSuggestionService } from '@/lib/ai/services/notebook-suggestion.service'
+
+export async function POST(req: NextRequest) {
+  try {
+    const session = await auth()
+    if (!session?.user?.id) {
+      return NextResponse.json({ error: 'Unauthorized' }, { status: 401 })
+    }
+
+    const body = await req.json()
+    const { noteContent, language = 'en' } = body
+
+    if (!noteContent || typeof noteContent !== 'string') {
+      return NextResponse.json({ error: 'noteContent is required' }, { status: 400 })
+    }
+
+    // Minimum content length for suggestion (20 words as per specs)
+    const wordCount = noteContent.trim().split(/\s+/).length
+    if (wordCount < 20) {
+      return NextResponse.json({
+        suggestion: null,
+        reason: 'content_too_short',
+        message: 'Note content too short for meaningful suggestion'
+      })
+    }
+
+    // Get suggestion from AI service
+    const suggestedNotebook = await notebookSuggestionService.suggestNotebook(
+      noteContent,
+      session.user.id,
+      language
+    )
+
+    return NextResponse.json({
+      suggestion: suggestedNotebook,
+      confidence: suggestedNotebook ? 0.8 : 0 // Placeholder confidence score
+    })
+  } catch (error) {
+    return NextResponse.json(
+      { error: 'Failed to generate suggestion' },
+      { status: 500 }
+    )
+  }
+}