chore(web): address Copilot review on #2128

Seven of the eight comments, plus the three suppressed ones (the same
double-cast class):

- Narrow the toast hooks to `InspectorClientEventSource`, the client's
  typed event-listener surface. A bare `EventTarget` cannot satisfy it
  (its listener takes an `Event`, the typed one a `TypedEventGeneric`
  with `detail`), so both tests now construct a real
  `InspectorClientEventTarget` and dispatch through `dispatchTypedEvent`
  rather than casting a stand-in. That failed to compile immediately and
  caught two bad fixtures: `task()` was a `Pick<Task, "status">` where
  the event map wants a full `Task`, and `toolCallTaskUpdated` was
  dispatched with no `task` at all.
- Narrow `useExportActions`'s three store parameters to the single
  clearing method each handler calls, so the test doubles are
  structurally checked instead of cast away.
- Build real `MessageEntry` fixtures (`timestamp` is a `Date`, not `0`),
  removing four more double casts.
- Fix a tautological assertion in useTabUiState.test: it compared a
  callback to itself, so it held however the identity changed. Every
  callback is now captured before the update and compared to those
  references.
- Reword `resetTabUiState`'s doc: `exhaustive-deps` cannot infer
  stability across a hook boundary, so the dependency IS named — the
  stability buys no churn, not omission.
- Justify the one remaining double cast in place, per the type-safety
  rule.

`useProgressToasts` still returns `void` rather than an object,
deliberately: it has nothing to return, and `{}` would imply an API that
is not there. Noted on the PR as the one deviation from #2128's
"returns one object" criterion.

Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/hooks/useExportActions.test.tsx

@@ -32,21 +32,21 @@ const { replayProtocolRequest } = vi.hoisted(() => ({
 }));
 vi.mock("../lib/protocolReplay", () => ({ replayProtocolRequest }));
 
-const request = (id: string, method: string): MessageEntry =>
-  ({
-    id,
-    direction: "request",
-    timestamp: 0,
-    message: { jsonrpc: "2.0", id: 1, method, params: { a: 1 } },
-  }) as unknown as MessageEntry;
+const AT = new Date(0);
 
-const logNotification = (id: string): MessageEntry =>
-  ({
-    id,
-    direction: "notification",
-    timestamp: 0,
-    message: { jsonrpc: "2.0", method: "notifications/message" },
-  }) as unknown as MessageEntry;
+const request = (id: string, method: string): MessageEntry => ({
+  id,
+  direction: "request",
+  timestamp: AT,
+  message: { jsonrpc: "2.0", id: 1, method, params: { a: 1 } },
+});
+
+const logNotification = (id: string): MessageEntry => ({
+  id,
+  direction: "notification",
+  timestamp: AT,
+  message: { jsonrpc: "2.0", method: "notifications/message" },
+});
 
 function harness(overrides: Partial<UseExportActionsParams> = {}) {
   const messageLogState = { clearMessages: vi.fn() };
@@ -55,12 +55,11 @@ function harness(overrides: Partial<UseExportActionsParams> = {}) {
   const setPinnedProtocolIds = vi.fn();
   const params: UseExportActionsParams = {
     activeServerId: "srv",
-    messageLogState:
-      messageLogState as unknown as UseExportActionsParams["messageLogState"],
-    fetchRequestLogState:
-      fetchRequestLogState as unknown as UseExportActionsParams["fetchRequestLogState"],
-    stderrLogState:
-      stderrLogState as unknown as UseExportActionsParams["stderrLogState"],
+    // Structurally checked against the hook's narrowed store parameters — each
+    // names only the clearing method these handlers call.
+    messageLogState,
+    fetchRequestLogState,
+    stderrLogState,
     messages: [],
     fetchRequests: [],
     logs: [],
@@ -281,9 +280,9 @@ describe("useExportActions", () => {
           {
             id: "r1",
             direction: "response",
-            timestamp: 0,
+            timestamp: AT,
             message: { jsonrpc: "2.0", id: 1, result: {} },
-          } as unknown as MessageEntry,
+          },
         ],
       });
       result.run((api) => api.onReplayProtocol("r1"));
@@ -298,9 +297,9 @@ describe("useExportActions", () => {
           {
             id: "r1",
             direction: "request",
-            timestamp: 0,
+            timestamp: AT,
             message: { jsonrpc: "2.0", id: 1, method: "ping" },
-          } as unknown as MessageEntry,
+          },
         ],
       });
       h.run((api) => api.onReplayProtocol("r1"));