feat: add YAML frontmatter, bitcoin-conventions skill, path rules, and Gitea CI

- Added YAML frontmatter to all 8 polish-* skills and sweep skill
  so Claude can auto-invoke them
- New bitcoin-conventions skill with PROUX UX methodology, sats display,
  address validation, Tor preferences, Lightning patterns
- Path-specific rules for containers (security hardening) and frontend
  (Vue/glassmorphism conventions)
- Gitea Actions: nightly security review and weekly dependency audit

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/nightly-security.yml

@@ -0,0 +1,45 @@
+name: Nightly Security Review
+on:
+  schedule:
+    - cron: '47 1 * * *'
+  workflow_dispatch:
+
+jobs:
+  security-review:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Claude Code
+        run: npm install -g @anthropic-ai/claude-code
+
+      - name: Run security review on recent changes
+        env:
+          ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
+        run: |
+          CHANGED=$(git diff --name-only HEAD~1..HEAD 2>/dev/null || echo "")
+          if [ -z "$CHANGED" ]; then
+            echo "No recent changes to review"
+            exit 0
+          fi
+
+          claude --print "Run a security review focused on these recently changed files:
+          $CHANGED
+
+          Check for:
+          - Constant-time comparison violations in crypto code
+          - Private key material in logs or error messages
+          - Floating-point Bitcoin amounts (must be integer sats)
+          - eval() or unsafe blocks without SAFETY comments
+          - Hardcoded credentials or secrets
+          - Missing input validation at API boundaries
+
+          Output a structured report with severity levels.
+          If any CRITICAL issues found, exit with code 1." > security-report.txt 2>&1
+
+          cat security-report.txt
+
+          if grep -qi "critical" security-report.txt; then
+            echo "::error::Critical security issues found — review security-report.txt"
+            exit 1
+          fi