feat: pictures table, Hetzner S3 upload/delete, auto-migration

- pictures table with UUID, status enum, timestamps, blurhash, design
- Auto-trigger updates updated_at on every row change
- POST /api/pictures/:id/upload  → upload file to Hetzner snakkimo bucket
- DELETE /api/pictures/:id       → removes DB row + Hetzner file
- PATCH /api/pictures/:id        → auto-sets published/blocked timestamps
- Migration runs on every server start (idempotent)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/index.js

@@ -3,6 +3,7 @@ const express = require('express');
 const cors = require('cors');
 const auth = require('./middleware/auth');
 const { pool } = require('./db');
+const migrate = require('./db-migrate');
 
 const app = express();
 const PORT = process.env.PORT || 3000;
@@ -23,6 +24,7 @@ app.get('/health', async (req, res) => {
 
 // Routes — protected by Bearer token
 app.use('/api', auth, require('./routes/index'));
+app.use('/api/pictures', auth, require('./routes/pictures'));
 
 // 404
 app.use((req, res) => {
@@ -35,6 +37,6 @@ app.use((err, req, res, next) => {
   res.status(500).json({ error: 'Internal server error' });
 });
 
-app.listen(PORT, '0.0.0.0', () => {
-  console.log(`snakkimo-API running on port ${PORT}`);
-});
+migrate()
+  .then(() => app.listen(PORT, '0.0.0.0', () => console.log(`snakkimo-API running on port ${PORT}`)))
+  .catch(err => { console.error('Migration failed:', err); process.exit(1); });