fix(ui): keep the session view open when selecting a log inside it (#35399)

Opening a session from the logs table stored no ?session_id (row clicks
called openLog, which deletes it), so session mode was derived from the
clicked row's session_total_count. Rows fetched by the session drawer
come from /spend/logs/session/ui, which does not enrich that field, so
selecting any log inside the session view swapped in an unenriched row
and collapsed the drawer to a single-log Trace view

Row clicks on a multi-call session's row now call openSession, and
selectLog writes ?session_id when the session view is active, so session
mode is anchored in the URL instead of derived from row data

ui/litellm-dashboard/src/components/view_logs/RequestLogsPanel.test.tsx

@@ -403,6 +403,41 @@ describe("RequestLogsPanel", () => {
         expect(drawer()).toHaveAttribute("data-session-id", "sess-1");
       });
     });
+
+    it("clicking a multi-call session's row writes ?session_id= alongside ?log_id=", async () => {
+      const user = userEvent.setup();
+      respondWith([
+        logEntry({ request_id: "req-llm", call_type: "acompletion", session_id: "sess-1", session_total_count: 3 }),
+        logEntry({ request_id: "req-llm-2", call_type: "acompletion", session_id: "sess-1", session_total_count: 3 }),
+      ]);
+      renderWithProviders(<RequestLogsPanel {...defaultProps} />);
+
+      await waitFor(() => expect(row("req-llm")).not.toBeNull());
+      await user.click(row("req-llm") as HTMLElement);
+
+      const params = new URLSearchParams(window.location.search);
+      expect(params.get("session_id")).toBe("sess-1");
+      expect(params.get("log_id")).toBe("req-llm");
+      await waitFor(() => expect(drawer()).toHaveAttribute("data-session-id", "sess-1"));
+    });
+
+    it("selecting another log while a session view is open keeps the session open", async () => {
+      const user = userEvent.setup();
+      window.history.replaceState(null, "", "/logs/?log_id=req-llm");
+      respondWith([
+        logEntry({ request_id: "req-llm", call_type: "acompletion", session_id: "sess-1", session_total_count: 3 }),
+        logEntry({ request_id: "req-unenriched" }),
+      ]);
+      renderWithProviders(<RequestLogsPanel {...defaultProps} />);
+
+      await waitFor(() => expect(drawer()).toHaveAttribute("data-session-id", "sess-1"));
+
+      await user.click(screen.getByRole("button", { name: "select-next-log" }));
+
+      await waitFor(() => expect(drawer()).toHaveAttribute("data-log-id", "req-unenriched"));
+      expect(new URLSearchParams(window.location.search).get("session_id")).toBe("sess-1");
+      expect(drawer()).toHaveAttribute("data-session-id", "sess-1");
+    });
   });
 
   describe("live tail", () => {

ui/litellm-dashboard/src/components/view_logs/RequestLogsPanel.tsx

@@ -235,9 +235,13 @@ export default function RequestLogsPanel({ accessToken, token, userRole, userID,
   const handleRowClick = useCallback(
     (log: LogEntry) => {
       setSelectedLog(log);
-      openLog(log.request_id);
+      if (log.session_id && (log.session_total_count || 1) > 1) {
+        openSession(log.session_id, log.request_id);
+      } else {
+        openLog(log.request_id);
+      }
     },
-    [openLog],
+    [openLog, openSession],
   );
 
   const handleSessionClick = useCallback(
@@ -253,9 +257,9 @@ export default function RequestLogsPanel({ accessToken, token, userRole, userID,
   const handleSelectLog = useCallback(
     (log: LogEntry) => {
       setSelectedLog(log);
-      selectLog(log.request_id);
+      selectLog(log.request_id, displaySessionId);
     },
-    [selectLog],
+    [selectLog, displaySessionId],
   );
 
   const handleKeyHashClick = useCallback((keyHash: string) => {

ui/litellm-dashboard/src/components/view_logs/logDetailRouting.ts

@@ -11,7 +11,7 @@ export interface LogDetailRouting {
   sessionId: string | null;
   openLog: (requestId: string) => void;
   openSession: (sessionId: string, requestId: string | null) => void;
-  selectLog: (requestId: string) => void;
+  selectLog: (requestId: string, sessionId?: string | null) => void;
   close: () => void;
 }
 
@@ -36,9 +36,12 @@ export function useLogDetailRouting(): LogDetailRouting {
     });
   }, []);
 
-  const selectLog = useCallback((requestId: string) => {
+  const selectLog = useCallback((requestId: string, sessionId?: string | null) => {
     navigateWithParams((params) => {
       params.set(LOG_ID_QUERY_PARAM, requestId);
+      if (sessionId) {
+        params.set(SESSION_ID_QUERY_PARAM, sessionId);
+      }
     }, "replace");
   }, []);