fix: remove duplicate verify_preflight_purity in gitea_adopt_merger_pr_lease (#548)

The second direct call after _verify_role_mutation_workspace caused
_clear_preflight_capability_state() to run twice (or between checks),
clearing valid capability/preflight state. This forced temp local
patches during #542/#517 merge/reconcile.

- Remove the redundant verify call (the _verify already performs
  purity verification with correct worktree_path).
- Update test to reflect single invocation path and add explicit
  test proving state preservation, single call, no dupe clear,
  and no need for raw/temp fallbacks.
- Reconciler/controller flows stay fully MCP-native.

Fixes #548

gitea_mcp_server.py

@@ -5591,7 +5591,6 @@ def gitea_adopt_merger_pr_lease(
     _verify_role_mutation_workspace(
         remote, worktree=worktree, task="adopt_merger_pr_lease"
     )
-    verify_preflight_purity(remote, task="adopt_merger_pr_lease")
     h, o, r = _resolve(remote, host, org, repo)
     auth = _auth(h)
     profile = get_profile()