fix: use gitleaks CLI instead of licensed action, fix lint errors

- Replace gitleaks-action (requires paid license) with direct CLI
  invocation -- same engine, no license needed
- Fix ruff I001 import sorting in voice.py and test_llm.py
- Remove unused imports: _chat_request (test_llm), Path (test_music)
- Remove unused assignment: original_spawn (test_voice)

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

.gitea/workflows/ci.yml

@@ -12,9 +12,12 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: gitleaks/gitleaks-action@v2
-        env:
-          GITLEAKS_LICENSE: ${{ secrets.GITLEAKS_LICENSE }}
+      - name: Install gitleaks
+        run: |
+          curl -sSL https://github.com/gitleaks/gitleaks/releases/latest/download/gitleaks_8.24.3_linux_x64.tar.gz \
+            | tar xz -C /usr/local/bin gitleaks
+      - name: Scan for secrets
+        run: gitleaks detect --source . --verbose
 
   lint:
     runs-on: ubuntu-latest