docs(rpa): mandate poll_until and raise kit min to 1.2.11 (v1.0.78)

Backport bounded readiness-wait convention and thin env/readiness error codes from platform-kit 1.2.11 into template docs, examples, and default platform_kit_min_version.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/_support.py

@@ -35,7 +35,7 @@ def get_skill_root() -> str:
     return _SKILL_ROOT
 
 
-def platform_kit_version_patch(version: str = "1.2.2"):
+def platform_kit_version_patch(version: str = "1.2.11"):
     """Mock installed jiangchang-platform-kit version for health/diagnostics tests."""
     from unittest.mock import patch