Commit the env example that .env* was swallowing

create-next-app's .gitignore matches .env*, which takes the example with it.
The file documenting every variable the app needs was the one file in the
pattern that has to be tracked.

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

.gitignore

@@ -30,8 +30,10 @@ yarn-debug.log*
 yarn-error.log*
 .pnpm-debug.log*
 
-# env files (can opt-in for committing if needed)
+# env files. The real ones hold DATABASE_URL, the Authentik client secret and
+# the agent token; the example is the documentation and must be committed.
 .env*
+!.env.example
 
 # vercel
 .vercel