fix: address Copilot review on the list-salvage path (#1909)

Three real defects it caught, plus the tests it asked for:

- The strict `tools/list` aggregate is filtered by the SDK for invalid
  `x-mcp-header` annotations (SEP-2243), but the salvage path was not: one
  ordinary malformed tool would trip the fallback and readmit every
  invalid-header tool beside it. Salvaged tools now go through the same scan.

- `markResponseRejected` resolves "the last response received for this method",
  and the re-walk answers that same method — so the mark landed on a salvage
  page that succeeded while the actually-invalid response rendered clean. The
  correlation id is now captured before the re-walk.

- The report was cleared only on an explicit `disconnect()`. The route out that
  tears down nothing (`onerror` with no `onclose`) carried it into the next
  connection, so it is now cleared on the start-clean `resetSessionState()` path
  as well.

Fixing the first exposed two more, both found by the new test:

- The modern (2026-07-28) codec validates a result against the spec schema
  before the caller's, so a lenient `client.request` is rejected exactly as the
  strict one was — there was no salvage on the modern leg at all. It now goes
  through the raw-wire channel that exists for the modern `tasks/*` methods.
  `withModernEnvelope` is split out of `withModernTaskEnvelope` so a list
  request doesn't claim the tasks extension the user may have disabled.

- A malformed tool also blanked the SEP-2243 excluded set, leaving a tool that
  vanished for an invalid header with no explanation — #1909's own complaint one
  level down. The scan walk now tolerates a malformed sibling.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/test/core/react/useInspectorClient.test.tsx

@@ -144,6 +144,76 @@ describe("useInspectorClient", () => {
     expect(result.current.excludedTools).toEqual([]);
   });
 
+  it("subscribes to malformedListItemsChange and updates (#1909)", () => {
+    const client = new FakeInspectorClient();
+    const { result } = renderHook(() => useInspectorClient(client));
+    expect(result.current.malformedListItems).toEqual([]);
+    const malformed = [
+      {
+        method: "resources/templates/list",
+        index: 1,
+        label: "array_annotations",
+        reason: "annotations: Invalid input (expected object)",
+      },
+    ];
+    act(() => {
+      client.setMalformedListItems(malformed);
+    });
+    expect(result.current.malformedListItems).toEqual(malformed);
+  });
+
+  it("seeds malformedListItems from the client it is given (#1909)", () => {
+    // A client that already salvaged before this hook mounted (a screen opened
+    // after the connect-time list load) must show the report immediately.
+    const client = new FakeInspectorClient({ status: "connected" });
+    const malformed = [
+      { method: "tools/list", index: 0, reason: "name: expected string" },
+    ];
+    client.setMalformedListItems(malformed);
+    const { result } = renderHook(() => useInspectorClient(client));
+    expect(result.current.malformedListItems).toEqual(malformed);
+  });
+
+  it("resets malformedListItems to [] when client becomes null (#1909)", () => {
+    const client = new FakeInspectorClient({ status: "connected" });
+    client.setMalformedListItems([
+      { method: "tools/list", index: 0, reason: "name: expected string" },
+    ]);
+    const { result, rerender } = renderHook(({ c }) => useInspectorClient(c), {
+      initialProps: { c: client as FakeInspectorClient | null },
+    });
+    expect(result.current.malformedListItems.length).toBe(1);
+    rerender({ c: null });
+    expect(result.current.malformedListItems).toEqual([]);
+  });
+
+  it("re-seeds malformedListItems on a client swap, not the old server's (#1909)", () => {
+    const first = new FakeInspectorClient({ status: "connected" });
+    first.setMalformedListItems([
+      { method: "tools/list", index: 0, reason: "name: expected string" },
+    ]);
+    const second = new FakeInspectorClient({ status: "connected" });
+    const { result, rerender } = renderHook(({ c }) => useInspectorClient(c), {
+      initialProps: { c: first as FakeInspectorClient },
+    });
+    expect(result.current.malformedListItems).toHaveLength(1);
+    rerender({ c: second });
+    expect(result.current.malformedListItems).toEqual([]);
+  });
+
+  it("stops listening for malformedListItemsChange after unmount (#1909)", () => {
+    const client = new FakeInspectorClient({ status: "connected" });
+    const { result, unmount } = renderHook(() => useInspectorClient(client));
+    unmount();
+    act(() => {
+      client.setMalformedListItems([
+        { method: "tools/list", index: 0, reason: "name: expected string" },
+      ]);
+    });
+    // A listener left attached would update state on an unmounted tree.
+    expect(result.current.malformedListItems).toEqual([]);
+  });
+
   it("resets protocolEra / discoverResult to defaults when client becomes null", () => {
     const client = new FakeInspectorClient({
       status: "connected",