fix(frontend): clear yoke from session route writes

Date filters can be cleared while AnalyticsPage is unmounted, such as from session detail. In that path the page-level clear effect cannot run, so the stored yoke range can survive and later reseed the cleared dates when the analytics view remounts.

Clear the stored yoke from the shared sessions route writeback whenever date/window intent is removed from the URL params. This keeps sidebar clears, detail-route clears, and the analytics remount path aligned.

Author: wesm

frontend/src/App.svelte

@@ -33,13 +33,15 @@
   import { starred } from "./lib/stores/starred.svelte.js";
   import { pins } from "./lib/stores/pins.svelte.js";
   import { settings } from "./lib/stores/settings.svelte.js";
+  import { yokedDates } from "./lib/stores/yokedDates.svelte.js";
   import { setAuthToken, getAuthToken, setServerUrl, getBase } from "./lib/api/runtime.js";
   import { setupVisibilityHealthCheck } from "./lib/utils/health.js";
   import { registerShortcuts } from "./lib/utils/keyboard.js";
   import { shouldAutoSwitchTranscriptModeToNormal } from "./lib/utils/transcript-mode.js";
   import {
     filterParamsEqual,
     hasFilterParams,
+    sessionDateIntentCleared,
     sessionRouteParamsForDetailExit,
     sessionRouteParamsForFilters,
   } from "./lib/stores/sessionRouteParams.js";
@@ -228,6 +230,14 @@
     messageListRef?.scrollToOrdinal(ordinal);
   }
 
+  function clearYokeForClearedSessionDates(
+    nextParams: Record<string, string>,
+  ): void {
+    if (sessionDateIntentCleared(router.params, nextParams)) {
+      yokedDates.clear();
+    }
+  }
+
   let lastDetailFilterParamsSignature: string | null = $state(null);
 
   // React to route changes: reload sessions and apply URL params.
@@ -315,11 +325,13 @@
             lastDetailFilterParamsSignature !== filterParamsSignature &&
             !filterParamsEqual(router.params, nextParams)
           ) {
+            clearYokeForClearedSessionDates(nextParams);
             router.replaceParams(nextParams);
           }
           lastDetailFilterParamsSignature = filterParamsSignature;
           return;
         }
+        clearYokeForClearedSessionDates(nextParams);
         router.navigateToSession(activeId, nextParams);
         lastDetailFilterParamsSignature = filterParamsSignature;
       } else {
@@ -339,6 +351,7 @@
               filterParams,
               router.params,
             );
+        clearYokeForClearedSessionDates(nextParams);
         router.navigateFromSession(nextParams);
         lastDetailFilterParamsSignature = null;
       }
@@ -360,6 +373,7 @@
       if (route !== "sessions") return;
       if (router.sessionId) return;
       if (filterParamsEqual(router.params, newParams)) return;
+      clearYokeForClearedSessionDates(newParams);
       router.replaceParams(newParams);
     });
   });

frontend/src/App.test.ts

@@ -106,6 +106,28 @@ describe("App session URL date state", () => {
     );
   });
 
+  it("clears stored yoke when session date params are removed while analytics is unmounted", () => {
+    const syncUrlBlock = appSourceSlice(
+      "// Sync active session to URL.",
+      "\n\n  // URL write-back",
+    );
+    const writeBackBlock = appSourceSlice(
+      "// URL write-back",
+      "\n\n  function showAbout",
+    );
+
+    expect(source).toContain("import { yokedDates");
+    expect(source).toContain("function clearYokeForClearedSessionDates");
+    expect(source).toContain("sessionDateIntentCleared(");
+    expect(source).toContain("yokedDates.clear();");
+    expect(syncUrlBlock).toContain(
+      "clearYokeForClearedSessionDates(nextParams);",
+    );
+    expect(writeBackBlock).toContain(
+      "clearYokeForClearedSessionDates(newParams);",
+    );
+  });
+
   it("clears detail filter signatures outside session detail routes", () => {
     const syncUrlBlock = appSourceSlice(
       "// Sync active session to URL.",

frontend/src/lib/stores/sessionRouteParams.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from "vite-plus/test";
 import {
   SESSION_FILTER_KEYS,
+  sessionDateIntentCleared,
   sessionRouteParamsForDetailExit,
   sessionRouteParamsForFilters,
 } from "./sessionRouteParams.js";
@@ -102,6 +103,25 @@ describe("session route params", () => {
     expect(params).toEqual({ project: "agentsview" });
   });
 
+  it("detects removed session date intent", () => {
+    expect(sessionDateIntentCleared(
+      {
+        date_from: "2026-05-21",
+        date_to: "2026-06-20",
+        window_days: "30",
+      },
+      { project: "agentsview" },
+    )).toBe(true);
+    expect(sessionDateIntentCleared(
+      { window_days: "30" },
+      { window_days: "30", project: "agentsview" },
+    )).toBe(false);
+    expect(sessionDateIntentCleared(
+      { project: "agentsview" },
+      { project: "agentsview" },
+    )).toBe(false);
+  });
+
   it("prefers direct detail URL params over saved filters on exit", () => {
     const params = sessionRouteParamsForDetailExit(
       { project: "saved", agent: "codex" },

frontend/src/lib/stores/sessionRouteParams.ts

@@ -31,6 +31,21 @@ function hasFixedSessionDateParams(
   return !!params["date"] || !!params["date_from"] || !!params["date_to"];
 }
 
+function hasSessionDateIntent(
+  params: Record<string, string>,
+): boolean {
+  return hasFixedSessionDateParams(params) ||
+    !!params[SESSION_ANALYTICS_WINDOW_PARAM];
+}
+
+export function sessionDateIntentCleared(
+  currentParams: Record<string, string>,
+  nextParams: Record<string, string>,
+): boolean {
+  return hasSessionDateIntent(currentParams) &&
+    !hasSessionDateIntent(nextParams);
+}
+
 function isValidWindowDaysParam(raw: string | undefined): raw is string {
   if (!raw) return false;
   const n = Number.parseInt(raw, 10);