Electronics Catalog: API, MCP server, frontend and deployment

Verified catalogue of mobiles and laptops sold in India, collected from
real retail listings (FastAPI backend, React frontend, Postgres/pgvector).

- REST API under /api/elec (read-only catalogue; admin endpoints need login)
- MCP server (FastMCP) at /mcp/ with list_categories, search_products,
  get_product and price_history tools
- Real ratings and reviews read from product pages and search results
- Production Dockerfile (requirements-api.txt, no PyTorch) and
  .env.production.example; remote database only via an explicit
  ELEC_ALLOW_REMOTE_DB host/name allowlist
- docs/API.md: endpoint and MCP reference with live examples

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

backend/app/electronics/db/migrate.py

@@ -0,0 +1,63 @@
+"""Tiny migration runner for the numbered SQL files in ./migrations.
+
+Each file runs once, in its own transaction, and is recorded in
+elec.schema_migrations with a checksum. Editing an applied file is refused
+rather than silently ignored - add a new numbered file instead.
+"""
+from __future__ import annotations
+
+import hashlib
+import logging
+from pathlib import Path
+from typing import List
+
+from app.electronics.db.connection import connect
+
+logger = logging.getLogger(__name__)
+
+MIGRATIONS_DIR = Path(__file__).resolve().parent / "migrations"
+
+_BOOTSTRAP = """
+CREATE SCHEMA IF NOT EXISTS elec;
+CREATE TABLE IF NOT EXISTS elec.schema_migrations (
+    version    TEXT PRIMARY KEY,
+    checksum   TEXT NOT NULL,
+    applied_at TIMESTAMPTZ NOT NULL DEFAULT now()
+);
+"""
+
+
+def _files() -> List[Path]:
+    return sorted(MIGRATIONS_DIR.glob("[0-9][0-9][0-9][0-9]_*.sql"))
+
+
+def run_migrations() -> List[str]:
+    """Apply pending migrations. Returns the versions applied by this call."""
+    applied_now: List[str] = []
+    with connect() as conn:
+        conn.execute(_BOOTSTRAP)
+        conn.commit()
+        done = {
+            r["version"]: r["checksum"]
+            for r in conn.execute("SELECT version, checksum FROM elec.schema_migrations")
+        }
+        for path in _files():
+            sql = path.read_text(encoding="utf-8")
+            checksum = hashlib.sha256(sql.encode("utf-8")).hexdigest()
+            version = path.stem
+            if version in done:
+                if done[version] != checksum:
+                    raise RuntimeError(
+                        f"Migration {version} was edited after it was applied. "
+                        f"Revert the edit and add a new numbered migration instead."
+                    )
+                continue
+            logger.info("Applying migration %s", version)
+            with conn.transaction():
+                conn.execute(sql)
+                conn.execute(
+                    "INSERT INTO elec.schema_migrations (version, checksum) VALUES (%s, %s)",
+                    (version, checksum),
+                )
+            applied_now.append(version)
+    return applied_now