Enable branch protection and Woodpecker for forgebot repos

- Add forgebot team with unkinben and benvin members
- Enable branch protection on main for forgebot and forgebot-skills
- Team-based approval and merge whitelists
- Register both repos with Woodpecker CI
- CI status checks: pre-commit, test, build (forgebot); validate (skills)

config/git.unkin.net/unkin/repository/forgebot-skills.yaml

@@ -1,2 +1,15 @@
 description: "Skill definitions for forgebot agents"
 private: false
+default_branch: "main"
+default_delete_branch_after_merge: true
+default_merge_style: "squash"
+branch_protection:
+  - rule_name: "main"
+    enable_push: false
+    status_check_contexts:
+      - "ci/woodpecker/pr/validate"
+    approval_whitelist_teams:
+      - "forgebot"
+    merge_whitelist_teams:
+      - "forgebot"
+woodpecker: true