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/echo/connections/route.ts

@@ -0,0 +1,85 @@
+import { NextRequest, NextResponse } from 'next/server'
+import { auth } from '@/auth'
+import { memoryEchoService } from '@/lib/ai/services/memory-echo.service'
+
+/**
+ * GET /api/ai/echo/connections?noteId={id}&page={page}&limit={limit}
+ * Fetch all connections for a specific note
+ */
+export async function GET(req: NextRequest) {
+  try {
+    const session = await auth()
+
+    if (!session?.user?.id) {
+      return NextResponse.json(
+        { error: 'Unauthorized' },
+        { status: 401 }
+      )
+    }
+
+    // Get query parameters
+    const { searchParams } = new URL(req.url)
+    const noteId = searchParams.get('noteId')
+    const page = parseInt(searchParams.get('page') || '1')
+    const limit = parseInt(searchParams.get('limit') || '10')
+
+    // Validate noteId
+    if (!noteId) {
+      return NextResponse.json(
+        { error: 'noteId parameter is required' },
+        { status: 400 }
+      )
+    }
+
+    // Validate pagination parameters
+    if (page < 1 || limit < 1 || limit > 50) {
+      return NextResponse.json(
+        { error: 'Invalid pagination parameters. page >= 1, limit between 1 and 50' },
+        { status: 400 }
+      )
+    }
+
+    // Get all connections for the note
+    const allConnections = await memoryEchoService.getConnectionsForNote(noteId, session.user.id)
+
+    // Calculate pagination
+    const total = allConnections.length
+    const startIndex = (page - 1) * limit
+    const endIndex = startIndex + limit
+    const paginatedConnections = allConnections.slice(startIndex, endIndex)
+
+    // Format connections for response
+    const connections = paginatedConnections.map(conn => {
+      // Determine which note is the "other" note (not the target note)
+      const isNote1Target = conn.note1.id === noteId
+      const otherNote = isNote1Target ? conn.note2 : conn.note1
+
+      return {
+        noteId: otherNote.id,
+        title: otherNote.title,
+        content: otherNote.content,
+        createdAt: otherNote.createdAt,
+        similarity: conn.similarityScore,
+        daysApart: conn.daysApart
+      }
+    })
+
+    return NextResponse.json({
+      connections,
+      pagination: {
+        total,
+        page,
+        limit,
+        totalPages: Math.ceil(total / limit),
+        hasNext: endIndex < total,
+        hasPrev: page > 1
+      }
+    })
+
+  } catch (error) {
+    return NextResponse.json(
+      { error: 'Failed to fetch connections' },
+      { status: 500 }
+    )
+  }
+}