fix: normalize env var comparisons to be case-insensitive

All NODE_ENV, DEMO_MODE, OIDC_ONLY, FORCE_HTTPS, COOKIE_SECURE, and
ALLOW_INTERNAL_NETWORK checks now use .toLowerCase() so values like
'Production' or 'True' behave identically to their lowercase forms.
Also adds APP_VERSION to the startup banner.

server/src/db/database.ts

@@ -47,7 +47,7 @@ const db = new Proxy({} as Database.Database, {
   },
 });
 
-if (process.env.DEMO_MODE === 'true') {
+if (process.env.DEMO_MODE?.toLowerCase() === 'true') {
   try {
     const { seedDemoData } = require('../demo/demo-seed');
     seedDemoData(_db);