Add vault-plugin-secrets-apptoken repository

Provision the Gitea repo for a generic app-token Vault/OpenBao secrets
engine that issues short-lived signed JWTs for self-made services,
replacing per-app static bearer Secrets. Mirrors the existing plugin repo
entries (squash-only, main branch protection, PR CI checks).

Claude-Session: https://claude.ai/code/session_01JUoARVdmhxKQHyyyp1pxeT

config/git.unkin.net/unkin/repository/vault-plugin-secrets-apptoken.yaml

@@ -0,0 +1,19 @@
+description: "HashiCorp Vault / OpenBao secrets engine issuing short-lived signed JWT app tokens (per-app roles, offline JWKS validation) for self-made services"
+private: false
+default_branch: "main"
+default_delete_branch_after_merge: true
+# Squash-only: the gitea provider has no "default merge style", so we restrict
+# the allowed styles to squash to force it.
+allow_merge_commits: false
+allow_rebase: false
+allow_rebase_explicit: false
+allow_squash_merge: true
+branch_protection:
+  - rule_name: "main"
+    enable_push: false
+    status_check_contexts:
+      - "ci/woodpecker/pr/pre-commit"
+      - "ci/woodpecker/pr/build"
+      - "ci/woodpecker/pr/test"
+    approval_whitelist_teams:
+      - "Owners"