fix: add python3 to dependencies and improve package name extraction logic

.gitea/workflows/build.yaml

@@ -14,7 +14,7 @@ jobs:
         run: |
           sudo apt-get update
           sudo apt-get install -y \
-            build-essential git ca-certificates curl tar gzip
+            build-essential git ca-certificates curl tar gzip python3
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -62,19 +62,10 @@ jobs:
         run: |
           set -e
           if [ -f Cargo.toml ]; then
-            PKG_NAME="$(cargo metadata --no-deps --format-version=1 | python3 - <<'PY'
-import json
-import sys
-
-data = json.load(sys.stdin)
-for pkg in data.get("packages", []):
-    for target in pkg.get("targets", []):
-        if "bin" in target.get("kind", []):
-            print(target.get("name", ""))
-            raise SystemExit(0)
-print("")
-PY
-)"
+            PKG_NAME="$(cargo metadata --no-deps --format-version=1 2>/dev/null | python3 -c 'import json,sys; data=json.load(sys.stdin); names=[t.get("name","") for p in data.get("packages", []) for t in p.get("targets", []) if "bin" in t.get("kind", [])]; print(names[0] if names else "")')"
+            if [ -z "${PKG_NAME:-}" ]; then
+              PKG_NAME="$(sed -n 's/^name = \"\\(.*\\)\"/\\1/p' Cargo.toml | head -n 1)"
+            fi
           fi
           if [ -z "${PKG_NAME:-}" ]; then
             FULL="${GITHUB_REPOSITORY:-}"