Fix Coolify startup and add GitHub-to-Gitea deploy walkthrough

COOLIFY_GITEA_WALKTHROUGH.md

@@ -0,0 +1,53 @@
+# Coolify + Gitea Walkthrough
+
+This repository is set up so:
+- `upstream` = GitHub source (`https://github.com/otangid/muslim-api.git`)
+- `origin` = your Gitea repo (`https://git.backoffice.biz.id/dwindown/muslim-api.git`)
+
+## 1) One-time remote setup
+
+Run from this repo root:
+
+```bash
+git remote rename origin upstream
+git remote add origin https://git.backoffice.biz.id/dwindown/muslim-api.git
+git remote -v
+```
+
+Expected:
+- `upstream` points to GitHub
+- `origin` points to Gitea
+
+## 2) First push to Gitea
+
+After your local commit is ready:
+
+```bash
+git push -u origin main
+```
+
+## 3) Command flow for each update
+
+When GitHub has new commits and you want to redeploy via Coolify:
+
+```bash
+git checkout main
+git fetch upstream
+git pull --ff-only upstream main
+git push origin main
+```
+
+Coolify will redeploy when it detects the new commit on your Gitea branch.
+
+## 4) Optional quick checks before push
+
+```bash
+git status
+git log --oneline --decorate -n 5
+```
+
+## Notes
+
+- App startup now does not require a physical `.env` file.
+- Server uses `PORT` from environment, with fallback to `3000`.
+- Configure your runtime environment variables in Coolify UI.