ci: publish releases to Gitea instead of GitHub

The workflow was written for github.com: actions/upload-artifact failed on
the Gitea runner, softprops/action-gh-release only talks to the GitHub API,
and gen-manifest.js hardcoded github.com URLs.

- drop the artifact upload (release assets are the deliverable)
- upload release assets with tools/release-gitea.js, a dependency-free
  Gitea API client; re-running a tag replaces the attachments
- gen-manifest.js takes --server/PUBLIC_SERVER_URL and knows that Gitea
  spells the latest-asset URL /releases/download/latest/<file>
- PUBLIC_SERVER_URL is set explicitly because the runner only sees the
  instance's internal LAN address

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

tools/gen-manifest.js

@@ -7,12 +7,16 @@
  *                             can be added under Homebrew Channel ->
  *                             Settings -> Add repository
  *
- * Both are uploaded as release assets, so the stable repository URL is
- *   https://github.com/<owner>/<repo>/releases/latest/download/apps.json
- * and the manifest/ipk URLs inside point at the exact tagged release.
+ * Both are uploaded as release assets, so the repository URL stays stable
+ * across releases, while the manifest/ipk URLs inside point at the exact
+ * tagged release.
  *
- * Usage: node tools/gen-manifest.js [--repo owner/repo] [--tag v1.0.0]
- * On GitHub Actions both are picked up from the environment.
+ * Works against GitHub and Gitea/Forgejo; they spell the "latest release
+ * asset" URL differently, which is the only thing --server changes.
+ *
+ * Usage: node tools/gen-manifest.js [--server https://host] [--repo owner/repo]
+ *                                   [--tag v1.0.0]
+ * On GitHub/Gitea Actions all three are picked up from the environment.
  */
 'use strict';
 
@@ -34,6 +38,15 @@ const tag = arg(
   process.env.GITHUB_REF_TYPE === 'tag' ? process.env.GITHUB_REF_NAME : `v${pkg.version}`,
 );
 
+// PUBLIC_SERVER_URL wins over GITHUB_SERVER_URL because a Gitea runner is
+// handed the instance's internal URL (a LAN address), which is useless in a
+// manifest the TV has to fetch.
+const server = arg(
+  '--server',
+  process.env.PUBLIC_SERVER_URL || process.env.GITHUB_SERVER_URL || 'https://github.com',
+).replace(/\/+$/, '');
+const isGitHub = /(^|\.)github\.com$/i.test(new URL(server).hostname);
+
 const ipkName = `${pkg.name}_${pkg.version}_all.ipk`;
 const ipkPath = path.join(root, 'dist', ipkName);
 if (!fs.existsSync(ipkPath)) {
@@ -42,8 +55,12 @@ if (!fs.existsSync(ipkPath)) {
 }
 
 const ipk = fs.readFileSync(ipkPath);
-const releaseBase = repository
-  ? `https://github.com/${repository}/releases/download/${tag}`
+const releaseBase = repository ? `${server}/${repository}/releases/download/${tag}` : null;
+// GitHub: /releases/latest/download/<file>, Gitea: /releases/download/latest/<file>
+const latestBase = repository
+  ? isGitHub
+    ? `${server}/${repository}/releases/latest/download`
+    : `${server}/${repository}/releases/download/latest`
   : null;
 
 if (!releaseBase) {
@@ -65,7 +82,7 @@ const manifest = {
   title: pkg.title,
   appDescription: pkg.description,
   iconUri,
-  sourceUrl: repository ? `https://github.com/${repository}` : undefined,
+  sourceUrl: repository ? `${server}/${repository}` : undefined,
   rootRequired: true,
   ipkUrl: releaseBase ? `${releaseBase}/${ipkName}` : ipkName,
   ipkHash: { sha256: crypto.createHash('sha256').update(ipk).digest('hex') },
@@ -99,6 +116,6 @@ console.log(`repository: dist/apps.json`);
 if (repository) {
   console.log(
     `\nAdd this in Homebrew Channel -> Settings -> Add repository:\n` +
-      `  https://github.com/${repository}/releases/latest/download/apps.json`,
+      `  ${latestBase}/apps.json`,
   );
 }