v3: PostgreSQL backend — 20K rows seeded, server-side SQL filtering

- Added PostgreSQL 16 Alpine service to Docker Swarm stack
- db.py: schema for 17 tables, auto-seed from jv_data.json on first boot
- /api/dashboard/data?start=&end= — server-side SQL filtering
  All Time: 0.43s (was 4MB JSON download stuck loading)
  Filtered (12mo): 0.20s with ~90% less data transferred
- Dashboard HTML patched: calls API instead of static JSON
- Integer casting for IsNewCustomer/HasDiscount/IsFreeShipping
- Advisory lock prevents race condition during parallel worker startup
- Returning Revenue now shows correctly: £14.5M (75% of total)

app.py

@@ -1,7 +1,8 @@
 """JustVitamin × QuikCue — AI Content Engine
-Live proposal site with real Gemini-powered demos."""
+Live proposal site with real Gemini-powered demos.
+PostgreSQL-backed data dashboard."""
 
-import os, json, time, traceback
+import os, json, time, traceback, logging
 from pathlib import Path
 from flask import (Flask, render_template, jsonify, request,
                    send_from_directory, redirect)
@@ -9,6 +10,9 @@ from flask import (Flask, render_template, jsonify, request,
 from scraper import scrape_product, scrape_competitor
 from ai_engine import (generate_asset_pack, competitor_xray, pdp_surgeon,
                         optimise_pdp_copy, generate_product_images)
+from db import init_db, get_dashboard_data, get_meta
+
+logging.basicConfig(level=logging.INFO, format="%(asctime)s %(message)s")
 
 app = Flask(__name__,
             static_folder="static",
@@ -17,6 +21,13 @@ app = Flask(__name__,
 GEN_DIR = Path(__file__).parent / "generated"
 GEN_DIR.mkdir(exist_ok=True)
 
+# ── Init DB on startup ───────────────────────────────────────
+with app.app_context():
+    try:
+        init_db()
+    except Exception as e:
+        logging.error(f"DB init failed: {e}")
+
 # ── Page routes ──────────────────────────────────────────────
 
 @app.route("/")
@@ -32,6 +43,37 @@ def dashboard():
 def dashboard_files(filename):
     return send_from_directory("static/dashboard", filename)
 
+
+# ── Dashboard API (Postgres-backed) ─────────────────────────
+
+@app.route("/api/dashboard/data")
+def api_dashboard_data():
+    """Return filtered dashboard data from PostgreSQL.
+    Query params: ?start=YYYY-MM&end=YYYY-MM
+    Replaces the 4MB static JSON with fast server-side SQL filtering."""
+    start = request.args.get("start") or None
+    end = request.args.get("end") or None
+    try:
+        t0 = time.time()
+        data = get_dashboard_data(start, end)
+        data["_query_time"] = f"{time.time()-t0:.3f}s"
+        data["_source"] = "postgresql"
+        resp = jsonify(data)
+        resp.headers['Cache-Control'] = 'public, max-age=60'
+        return resp
+    except Exception as e:
+        traceback.print_exc()
+        return jsonify({"error": str(e)}), 500
+
+
+@app.route("/api/dashboard/meta")
+def api_dashboard_meta():
+    """Return just the meta info (fast, tiny)."""
+    try:
+        return jsonify(get_meta())
+    except Exception as e:
+        return jsonify({"error": str(e)}), 500
+
 @app.route("/proposal")
 def proposal():
     return send_from_directory("static/proposal", "index.html")
@@ -185,9 +227,23 @@ def api_generate_images():
 
 @app.route("/api/health")
 def health():
+    db_ok = False
+    try:
+        from db import get_conn
+        conn = get_conn()
+        cur = conn.cursor()
+        cur.execute("SELECT COUNT(*) FROM monthly")
+        count = cur.fetchone()[0]
+        cur.close()
+        conn.close()
+        db_ok = count > 0
+    except Exception:
+        pass
     return jsonify({
         "status": "ok",
         "gemini_key_set": bool(os.environ.get("GEMINI_API_KEY")),
+        "db_connected": db_ok,
+        "db_rows": count if db_ok else 0,
     })