Add app version display in Footer and implement version API endpoint

- Updated Footer.vue to show the application version for logged-in users.
- Added a new API endpoint to return the application version from package.json.
- Enhanced code-analysis.yml to require package version changes for main PRs.

scripts/check-package-version-changed.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+BASE_REF="${1:-origin/main}"
+BASE_BRANCH="${BASE_REF#origin/}"
+
+git fetch --no-tags --depth=1 origin "$BASE_BRANCH"
+
+current_version="$(node -e 'const fs = require("fs"); const pkg = JSON.parse(fs.readFileSync("package.json", "utf8")); process.stdout.write(String(pkg.version || ""));')"
+base_version="$(git show "$BASE_REF:package.json" | node -e 'let input = ""; process.stdin.setEncoding("utf8"); process.stdin.on("data", chunk => input += chunk); process.stdin.on("end", () => { const pkg = JSON.parse(input); process.stdout.write(String(pkg.version || "")); });')"
+
+if [ -z "$current_version" ]; then
+  echo "ERROR: package.json enthält kein version-Feld."
+  exit 1
+fi
+
+if [ "$current_version" = "$base_version" ]; then
+  echo "ERROR: package.json version wurde nicht geändert."
+  echo "Base ($BASE_REF): $base_version"
+  echo "Current: $current_version"
+  echo "Bitte version in package.json erhöhen, bevor nach main gemerged wird."
+  exit 1
+fi
+
+echo "package.json version changed: $base_version -> $current_version"