feat(ci): add automated workflows for releases and nightly builds

- Introduce workflows for auto-releases, changelog updates, and nightly builds
- Add scripts for version management, asset uploads, and cleanup tasks
- Remove deprecated GitHub workflow and optimize `.gitignore` entries
- Configure `git-cliff` for enhanced changelog generation with custom rules

.gitea/scripts/upload-asset.sh

@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Eingabeparameter
+FILE_PATH="$1"                      # z. B. ./dist/build.zip
+CUSTOM_NAME="${2:-}"               # optional: anderer Name unter dem das Asset gespeichert werden soll
+RELEASE_ID="${GT_RELEASE_ID:-}"       # aus Umgebung
+
+# Validierung
+if [[ -z "$RELEASE_ID" ]]; then
+  echo "❌ RELEASE_ID ist nicht gesetzt. Abbruch."
+  exit 1
+fi
+
+if [[ ! -f "$FILE_PATH" ]]; then
+  echo "❌ Datei '$FILE_PATH' existiert nicht. Abbruch."
+  exit 1
+fi
+
+# Default-Konfiguration
+TOKEN="${ACTIONS_RUNTIME_TOKEN:-<fallback_token>}"
+REPO="${GITHUB_REPOSITORY:-owner/example}"
+API="${GITHUB_API_URL:-https://gitea.example.tld/api/v1}"
+
+# Owner/Repo auflösen
+OWNER=$(echo "$REPO" | cut -d/ -f1)
+NAME=$(echo "$REPO" | cut -d/ -f2)
+
+# Dateiname setzen
+FILENAME="${CUSTOM_NAME:-$(basename "$FILE_PATH")}"
+
+echo "🔼 Uploading '$FILE_PATH' as '$FILENAME' to release ID $RELEASE_ID"
+
+# Upload
+curl -sf -X POST \
+  -H "Authorization: token $TOKEN" \
+  -F "attachment=@$FILE_PATH" \
+  "$API/repos/$OWNER/$NAME/releases/$RELEASE_ID/assets?name=$FILENAME"
+
+echo "✅ Upload abgeschlossen: $FILENAME"