test: satisfy pyright strict annotations on the new supervise RPC tests

Add parameter/return annotations to the fake resolver's propose_supervise /
poll_supervise, annotate the test helpers and the shared _ARGS payload, and
narrow the None-able poll result — no behavior change. pylint 9.83, pyright
clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/unit/test_egress_addon_request_flow.py

@@ -279,14 +279,15 @@ class _SuperviseRpcFake:
     propose_error: bool = False
 
     @property
-    def propose_calls(self) -> list:
+    def propose_calls(self) -> list[dict[str, str]]:
         if not hasattr(self, "_propose_calls"):
-            self._propose_calls: list = []
+            self._propose_calls: list[dict[str, str]] = []
         return self._propose_calls
 
     def propose_supervise(
-        self, source_ip, identity_token, *, tool, proposed_file, justification,
-    ):
+        self, source_ip: str, identity_token: str, *,
+        tool: str, proposed_file: str, justification: str,
+    ) -> str:
         del proposed_file, justification
         self.propose_calls.append(
             {"source_ip": source_ip, "identity_token": identity_token, "tool": tool}
@@ -295,7 +296,9 @@ class _SuperviseRpcFake:
             raise PolicyResolveError("orchestrator down")
         return "prop-1"
 
-    def poll_supervise(self, source_ip, identity_token, proposal_id):
+    def poll_supervise(
+        self, source_ip: str, identity_token: str, proposal_id: str,
+    ) -> dict[str, object]:
         del source_ip, identity_token, proposal_id
         if self.supervise_status is None:
             return {"status": "pending"}