docs: add action module API reference, update CHANGELOG and nav

- Add docs/api/action.md: full API reference for ActionConfigSchema and ActionArgumentSchema — field tables, factory methods, camelCase compat mapping, env-var interpolation, database integrity note, and complete YAML example
- Update docs/api/index.md: add cleveragents.action entry to module index
- Update mkdocs.yml: add 'Action Schema: api/action.md' to the API Reference nav
- Update CHANGELOG.md [Unreleased] Fixed: document plan use UNIQUE constraint violation fix (#4174, #4197)
- Clarify from_yaml_file ValueError semantics, document inputs_schema type as dict[str, Any] | None, and update A2A ASV benchmarks to pass method= requests after JSON-RPC migration

ISSUES CLOSED: #7472

benchmarks/a2a_facade_bench.py

@@ -40,11 +40,11 @@ class FacadeDispatchSuite:
 
     def setup(self) -> None:
         self.facade = A2aLocalFacade()
-        self.session_req = A2aRequest(operation="session.create")
+        self.session_req = A2aRequest(method="session.create", params={})
         self.plan_req = A2aRequest(
-            operation="plan.execute", params={"plan_id": "BENCH001"}
+            method="plan.execute", params={"plan_id": "BENCH001"}
         )
-        self.context_req = A2aRequest(operation="context.get")
+        self.context_req = A2aRequest(method="context.get", params={})
 
     def time_dispatch_session_create(self) -> None:
         self.facade.dispatch(self.session_req)
@@ -57,7 +57,7 @@ class FacadeDispatchSuite:
 
     def time_dispatch_all_operations(self) -> None:
         for op in self.facade.list_operations():
-            req = A2aRequest(operation=op)
+            req = A2aRequest(method=op, params={})
             self.facade.dispatch(req)
 
     def time_list_operations(self) -> None:

benchmarks/m6_acceptance_bench.py

@@ -50,17 +50,17 @@ class M6FacadeDispatchSuite:
 
     def time_session_create(self) -> None:
         """Benchmark session.create dispatch."""
-        self._facade.dispatch(A2aRequest(operation="session.create", params={}))
+        self._facade.dispatch(A2aRequest(method="session.create", params={}))
 
     def time_plan_create(self) -> None:
         """Benchmark plan.create dispatch."""
-        self._facade.dispatch(A2aRequest(operation="plan.create", params={}))
+        self._facade.dispatch(A2aRequest(method="plan.create", params={}))
 
     def time_plan_execute(self) -> None:
         """Benchmark plan.execute dispatch."""
         self._facade.dispatch(
             A2aRequest(
-                operation="plan.execute",
+                method="plan.execute",
                 params={"plan_id": "01M6SM0KE00000000000000001"},
             )
         )