feat(backend): add user_consents table schema

apps/backend/server.js

@@ -9,6 +9,7 @@ import axios from 'axios';
 import redisClient from './redis-client.js';
 import * as appMetrics from './src/metrics.js';
 import cors from 'cors';
+import helmet from 'helmet';
 import sqlite3 from 'sqlite3';
 import { promisify } from 'util';
 import path from 'path';
@@ -39,6 +40,23 @@ const __dirname = path.dirname(__filename);
 const app = express();
 const PORT = process.env.PORT || 3001;
 
+// Security headers via helmet. Strict-Transport-Security is only sent when
+// behind HTTPS (NODE_ENV=production). CSP is permissive enough for an API
+// that serves JSON + serves the frontend from a different origin.
+app.use(helmet({
+  contentSecurityPolicy: {
+    directives: {
+      defaultSrc: ["'self'"],
+      scriptSrc: ["'self'"],
+      styleSrc: ["'self'", "'unsafe-inline'"],
+      imgSrc: ["'self'", 'data:', 'https:'],
+      connectSrc: ["'self'"],
+      frameAncestors: ["'none'"],
+    },
+  },
+  crossOriginResourcePolicy: { policy: 'cross-origin' },
+}));
+
 // Structured JSON logger. The Pino OTel instrumentation attaches trace_id /
 // span_id to every log line so they can be correlated in Grafana.
 const logger = pino({
@@ -632,6 +650,50 @@ if (!pgPool) {
       `);
       await dbRun(`CREATE INDEX IF NOT EXISTS idx_pwd_reset_token ON password_reset_tokens(token)`);
     }
+    // ========== USER CONSENTS ==========
+    if (pgPool) {
+      await pgPool.query(`
+        CREATE TABLE IF NOT EXISTS user_consents (
+          id SERIAL PRIMARY KEY,
+          user_id INTEGER REFERENCES users(id) ON DELETE CASCADE,
+          session_id VARCHAR(255),
+          category VARCHAR(20) NOT NULL CHECK (category IN ('essential', 'analytics', 'preferences', 'health_data')),
+          granted BOOLEAN NOT NULL DEFAULT false,
+          created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+          updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
+        )
+      `);
+      await pgPool.query(`
+        CREATE UNIQUE INDEX IF NOT EXISTS idx_user_consents_user_cat
+        ON user_consents(user_id, category) WHERE user_id IS NOT NULL
+      `);
+      await pgPool.query(`
+        CREATE UNIQUE INDEX IF NOT EXISTS idx_user_consents_sess_cat
+        ON user_consents(session_id, category) WHERE session_id IS NOT NULL
+      `);
+      await pgPool.query(`CREATE INDEX IF NOT EXISTS idx_user_consents_user_id ON user_consents(user_id) WHERE user_id IS NOT NULL`);
+      await pgPool.query(`CREATE INDEX IF NOT EXISTS idx_user_consents_session_id ON user_consents(session_id) WHERE session_id IS NOT NULL`);
+    }
+    if (!pgPool) {
+      await dbRun(`
+        CREATE TABLE IF NOT EXISTS user_consents (
+          id INTEGER PRIMARY KEY AUTOINCREMENT,
+          user_id INTEGER,
+          session_id TEXT,
+          category TEXT NOT NULL CHECK (category IN ('essential', 'analytics', 'preferences', 'health_data')),
+          granted INTEGER NOT NULL DEFAULT 0,
+          created_at TEXT DEFAULT (datetime('now')),
+          updated_at TEXT DEFAULT (datetime('now')),
+          FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+        )
+      `);
+      try {
+        await dbRun(`CREATE UNIQUE INDEX IF NOT EXISTS idx_user_consents_user_cat ON user_consents(user_id, category) WHERE user_id IS NOT NULL`);
+      } catch (e) { if (!/duplicate/i.test(e.message)) throw e; }
+      try {
+        await dbRun(`CREATE UNIQUE INDEX IF NOT EXISTS idx_user_consents_sess_cat ON user_consents(session_id, category) WHERE session_id IS NOT NULL`);
+      } catch (e) { if (!/duplicate/i.test(e.message)) throw e; }
+    }
   } catch (err) {
     console.error('initDatabase failed:', err);
     throw err;