chore: switch GitHub widget and changelog to Gitea

- Sidebar "GitHub" widget renamed to "Gitea", links point to gitea.giersig.eu/giersig.eu
- Runtime widget JS fetches commits/repos/PRs directly from Gitea API
- Build-time data files (githubActivity, githubRepos) switched from GitHub API to Gitea API
- changelog.njk fetches from Gitea API directly with client-side commit categorisation
- GITEA_URL / GITEA_ORG added to deploy.yml build env

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

_data/githubRepos.js

@@ -1,48 +1,41 @@
 /**
- * GitHub Repos Data
- * Fetches public repositories from GitHub API
+ * Gitea Repos Data
+ * Fetches public repositories from Gitea org API
  */
 
 import { cachedFetch } from "../lib/data-fetch.js";
 
-export default async function () {
-  const username = process.env.GITHUB_USERNAME || "";
+const GITEA_URL = process.env.GITEA_URL || "https://gitea.giersig.eu";
+const GITEA_ORG = process.env.GITEA_ORG || "giersig.eu";
 
+export default async function () {
   try {
-    // Fetch public repos, sorted by updated date
-    const url = `https://api.github.com/users/${username}/repos?sort=updated&per_page=10&type=owner`;
+    const url = `${GITEA_URL}/api/v1/orgs/${GITEA_ORG}/repos?limit=10&sort=newest`;
 
     const repos = await cachedFetch(url, {
-      duration: "1h", // Cache for 1 hour
+      duration: "1h",
       type: "json",
-      fetchOptions: {
-        headers: {
-          Accept: "application/vnd.github.v3+json",
-          "User-Agent": "Eleventy-Site",
-        },
-      },
     });
 
-    // Filter and transform repos
     return repos
-      .filter((repo) => !repo.fork && !repo.private) // Exclude forks and private repos
+      .filter((repo) => !repo.fork && !repo.private)
       .map((repo) => ({
         name: repo.name,
         full_name: repo.full_name,
         description: repo.description,
         html_url: repo.html_url,
-        homepage: repo.homepage,
+        homepage: repo.website || repo.homepage,
         language: repo.language,
-        stargazers_count: repo.stargazers_count,
-        forks_count: repo.forks_count,
-        open_issues_count: repo.open_issues_count,
+        stargazers_count: repo.stars_count || repo.stargazers_count || 0,
+        forks_count: repo.forks_count || 0,
+        open_issues_count: repo.open_issues_count || 0,
         topics: repo.topics || [],
-        updated_at: repo.updated_at,
-        created_at: repo.created_at,
+        updated_at: repo.updated,
+        created_at: repo.created,
       }))
-      .slice(0, 10); // Limit to 10 repos
+      .slice(0, 10);
   } catch (error) {
-    console.error("Error fetching GitHub repos:", error.message);
+    console.error("Error fetching Gitea repos:", error.message);
     return [];
   }
 }