Fix: .env was never actually loaded for local dev

README said cp .env.example .env then npm run dev, but nothing ever
read the file into process.env — no dotenv, no --env-file. This
predates the admin UI work; just surfaced by actually trying to run
it. Fixed with Node's native --env-file flag on both dev and start
(no new dependency). Doesn't affect Docker, which gets its config
from docker-compose's environment: block directly, bypassing npm
scripts entirely (CMD calls node dist/index.js directly).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

package.json

@@ -4,9 +4,9 @@
   "license": "MIT",
   "type": "module",
   "scripts": {
-    "dev": "tsx watch src/index.ts",
+    "dev": "tsx watch --env-file=.env src/index.ts",
     "build": "tsc",
-    "start": "node dist/index.js"
+    "start": "node --env-file=.env dist/index.js"
   },
   "dependencies": {
     "express": "^4.19.2",