feat(FN-4191): complete Step 4 — add chat room settings controls

Fusion-Task-Id: FN-4191
Fusion-Task-Lineage: 00fddcfc-e136-41a5-84b1-b6f53b1692cb

packages/dashboard/app/components/SettingsModal.tsx

@@ -2037,6 +2037,52 @@ export function SettingsModal({
               </label>
               <small>Show the floating chat button in the dashboard. Chat is still accessible from the Chat tab in the mobile navigation.</small>
             </div>
+            <h4 className="settings-section-heading settings-section-heading--spaced">Chat Rooms</h4>
+            <div className="form-group">
+              <label htmlFor="chatRoomRecentVerbatimMessages">Recent verbatim room messages</label>
+              <input
+                id="chatRoomRecentVerbatimMessages"
+                type="number"
+                min="1"
+                className="input"
+                placeholder="12"
+                value={form.chatRoomRecentVerbatimMessages ?? ""}
+                onChange={(e) =>
+                  setForm((f) => ({ ...f, chatRoomRecentVerbatimMessages: Number(e.target.value) || undefined }))
+                }
+              />
+              <small>Number of most-recent chat-room messages kept verbatim in the responder transcript. Older messages are compacted into a summary block. Default: 12.</small>
+            </div>
+            <div className="form-group">
+              <label htmlFor="chatRoomCompactionFetchLimit">Room compaction fetch limit</label>
+              <input
+                id="chatRoomCompactionFetchLimit"
+                type="number"
+                min="1"
+                className="input"
+                placeholder="80"
+                value={form.chatRoomCompactionFetchLimit ?? ""}
+                onChange={(e) =>
+                  setForm((f) => ({ ...f, chatRoomCompactionFetchLimit: Number(e.target.value) || undefined }))
+                }
+              />
+              <small>Upper bound on messages fetched from the room store for compaction consideration. Default: 80.</small>
+            </div>
+            <div className="form-group">
+              <label htmlFor="chatRoomSummaryMaxChars">Room summary max characters</label>
+              <input
+                id="chatRoomSummaryMaxChars"
+                type="number"
+                min="200"
+                className="input"
+                placeholder="1500"
+                value={form.chatRoomSummaryMaxChars ?? ""}
+                onChange={(e) =>
+                  setForm((f) => ({ ...f, chatRoomSummaryMaxChars: Number(e.target.value) || undefined }))
+                }
+              />
+              <small>Hard cap on the synthesized "Earlier room context" summary block. Default: 1500.</small>
+            </div>
             <h4 className="settings-section-heading settings-section-heading--spaced">Capacity Risk Banner</h4>
             <div className="form-group">
               <label htmlFor="capacityRiskBannerEnabled" className="checkbox-label">

packages/dashboard/app/components/__tests__/SettingsModal.test.tsx

@@ -824,6 +824,35 @@ describe("SettingsModal", () => {
       expect(ephemeralToggle.checked).toBe(true);
     });
 
+    it("renders and saves chat room compaction controls", async () => {
+      renderModal({ initialSection: "general" });
+      await waitForSettingsModalReady();
+
+      expect(screen.getByRole("heading", { name: "Chat Rooms" })).toBeInTheDocument();
+
+      const recentInput = screen.getByLabelText("Recent verbatim room messages") as HTMLInputElement;
+      const fetchLimitInput = screen.getByLabelText("Room compaction fetch limit") as HTMLInputElement;
+      const summaryMaxInput = screen.getByLabelText("Room summary max characters") as HTMLInputElement;
+
+      expect(recentInput.placeholder).toBe("12");
+      expect(fetchLimitInput.placeholder).toBe("80");
+      expect(summaryMaxInput.placeholder).toBe("1500");
+
+      await userEvent.type(recentInput, "7");
+      await userEvent.type(fetchLimitInput, "60");
+      await userEvent.type(summaryMaxInput, "900");
+      await userEvent.click(screen.getByRole("button", { name: "Save" }));
+
+      await waitFor(() => {
+        expect(mockUpdateSettings).toHaveBeenCalled();
+      });
+
+      const payload = mockUpdateSettings.mock.calls[0][0] as Record<string, unknown>;
+      expect(payload.chatRoomRecentVerbatimMessages).toBe(7);
+      expect(payload.chatRoomCompactionFetchLimit).toBe(60);
+      expect(payload.chatRoomSummaryMaxChars).toBe(900);
+    });
+
     it("renders and saves GitHub tracking controls in the General section", async () => {
       renderModal({ initialSection: "general" });
       await waitForSettingsModalReady();