feat: add auto-incrementing version number (0.9.0.X) in footer

- Added version.json to track base version and build number
- Updated Gitea Actions workflow to bump build number on each deploy
- Footer now shows version number alongside commit hash
- Version passed as build arg through Docker build pipeline

Co-Authored-By: Paperclip <noreply@paperclip.ing>

next.config.ts

@@ -14,6 +14,7 @@ const nextConfig: NextConfig = {
   serverExternalPackages: ["pdfjs-dist", "drizzle-orm", "pg"],
   env: {
     NEXT_PUBLIC_BUILD_HASH: commitHash,
+    NEXT_PUBLIC_APP_VERSION: process.env.NEXT_PUBLIC_APP_VERSION || "0.9.0.1",
   },
 };