docs: sync documentation with actual repo state; adapt for Gitea

- Remove all .github references (removed in 6c644dd but docs still referenced)
- Rewrite review-pr skill to use Gitea API instead of gh CLI
- Add gitea-pr.sh helper for Gitea API calls (view/diff/files/comments)
- Update project structure tree: add scripts/, .woodpecker.yml, ci-cd.md,
  status-update-checklist.md, commit-docs-reminder.sh, RESEARCH-SDD-TOOLS.md
- Fix skills count 14 → 15 (add create-skill to DOCS.md)
- Remove .github references from CONTRIBUTING.md, SECURITY.md, init-project
- Add GITEA_TOKEN to .env.example
- Update CI/CD placeholder in RECOMMENDATIONS.md to Woodpecker

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

.env.example

@@ -31,6 +31,9 @@ NODE_ENV=development
 # --- Email ---
 # RESEND_API_KEY=
 
+# --- Gitea ---
+# GITEA_TOKEN=
+
 # --- CI/CD (Woodpecker) ---
 # WOODPECKER_TOKEN=
 # WOODPECKER_URL=https://ci.spektr.design