feat: implement Gitea update checks and installer management

docs/architecture.md

@@ -8,13 +8,16 @@
 4. In packaged builds, relaunches once after a fresh runtime install so NodeCG starts from a settled user-data runtime.
 5. Starts NodeCG with `nodecg/process-manager.ts`.
 6. Waits for HTTP readiness and shows loading -> main dashboard.
-7. On shutdown, runs a single graceful-stop flow to avoid orphan processes.
+7. Checks the configured Gitea latest-release endpoint for optional updates.
+8. On shutdown, runs a single graceful-stop flow to avoid orphan processes.
 
 ## Main modules
 
 - `config/runtime-config.ts`: read/validate env vars.
 - `nodecg/runtime-provisioner.ts`: install/refresh the managed runtime in the writable user data folder and report whether it changed.
 - `nodecg/process-manager.ts`: start, readiness, and stop for NodeCG; install/permission/port validation.
+- `updates/update-manager.ts`: optional Gitea release checks, installer download, and user-controlled install.
+- `updates/update-utils.ts`: release version comparison and installer asset selection.
 - `windows/window-factory.ts`: window creation and navigation policy.
 - `windows/navigation-security.ts`: internal navigation allowlist and safe external schemes.
 - `errors/error-presenter.ts`: fatal error presentation.

docs/troubleshooting.md

@@ -36,3 +36,10 @@
 
 - The configuration expects `static/icons/icon.icns`.
 - Create that file before running macOS packaging.
+
+## Updates do not appear
+
+- Check that `static/updates.json` has `"enabled": true` before building the installer.
+- The `apiUrl` must point to Gitea's latest release API: `/api/v1/repos/<owner>/<repo>/releases/latest`.
+- The release tag must be newer than the installed `package.json` version, for example `v0.2.0`.
+- The release must include an installer asset matching `assetPattern`, by default `Scoreko-setup-.*\.exe$`.