fix: address review #6388 findings

- Refactor projectsParams into filterParams({ includeProject: false })
  to eliminate duplicated date/timezone construction logic
- Add 7 tests for setProject behavior: toggle on/off, project param
  included in filtered panels but excluded from fetchProjects, and
  correct behavior with selectedDate active

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: wesm

frontend/src/lib/stores/analytics.svelte.ts

@@ -107,28 +107,39 @@ class AnalyticsStore {
     topSessions: 0,
   };
 
-  private baseParams(): AnalyticsParams {
+  private baseParams(
+    opts: { includeProject?: boolean } = {},
+  ): AnalyticsParams {
+    const includeProject = opts.includeProject ?? true;
     const p: AnalyticsParams = {
       from: this.from,
       to: this.to,
       timezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
     };
-    if (this.project) p.project = this.project;
+    if (includeProject && this.project) {
+      p.project = this.project;
+    }
     return p;
   }
 
   // Returns params narrowed to selectedDate when one is active.
-  // Used by summary, activity, and projects — but not heatmap.
-  private filterParams(): AnalyticsParams {
+  private filterParams(
+    opts: { includeProject?: boolean } = {},
+  ): AnalyticsParams {
+    const includeProject = opts.includeProject ?? true;
     if (this.selectedDate) {
-      return {
+      const p: AnalyticsParams = {
         from: this.selectedDate,
         to: this.selectedDate,
         timezone:
           Intl.DateTimeFormat().resolvedOptions().timeZone,
       };
+      if (includeProject && this.project) {
+        p.project = this.project;
+      }
+      return p;
     }
-    return this.baseParams();
+    return this.baseParams({ includeProject });
   }
 
   async fetchAll() {
@@ -217,30 +228,13 @@ class AnalyticsStore {
   // Projects chart always shows all projects (no project
   // filter) so the selected project can be highlighted in
   // context rather than shown in isolation.
-  private projectsParams(): AnalyticsParams {
-    if (this.selectedDate) {
-      return {
-        from: this.selectedDate,
-        to: this.selectedDate,
-        timezone:
-          Intl.DateTimeFormat().resolvedOptions().timeZone,
-      };
-    }
-    return {
-      from: this.from,
-      to: this.to,
-      timezone:
-        Intl.DateTimeFormat().resolvedOptions().timeZone,
-    };
-  }
-
   async fetchProjects() {
     const v = ++this.versions.projects;
     this.loading.projects = true;
     this.errors.projects = null;
     try {
       const data = await getAnalyticsProjects(
-        this.projectsParams(),
+        this.filterParams({ includeProject: false }),
       );
       if (this.versions.projects === v) {
         this.projects = data;

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

@@ -16,6 +16,7 @@ import type {
   SessionShapeResponse,
   VelocityResponse,
   ToolsAnalyticsResponse,
+  TopSessionsResponse,
 } from "../api/types.js";
 
 vi.mock("../api/client.js", () => ({
@@ -27,6 +28,7 @@ vi.mock("../api/client.js", () => ({
   getAnalyticsSessionShape: vi.fn(),
   getAnalyticsVelocity: vi.fn(),
   getAnalyticsTools: vi.fn(),
+  getAnalyticsTopSessions: vi.fn(),
 }));
 
 
@@ -97,6 +99,10 @@ function makeTools(): ToolsAnalyticsResponse {
   };
 }
 
+function makeTopSessions(): TopSessionsResponse {
+  return { metric: "messages", sessions: [] };
+}
+
 function mockAllAPIs() {
   vi.mocked(api.getAnalyticsSummary).mockResolvedValue(
     makeSummary(),
@@ -122,10 +128,14 @@ function mockAllAPIs() {
   vi.mocked(api.getAnalyticsTools).mockResolvedValue(
     makeTools(),
   );
+  vi.mocked(api.getAnalyticsTopSessions).mockResolvedValue(
+    makeTopSessions(),
+  );
 }
 
 function resetStore() {
   analytics.selectedDate = null;
+  analytics.project = "";
   analytics.from = "2024-01-01";
   analytics.to = "2024-01-31";
 }
@@ -301,3 +311,73 @@ describe("AnalyticsStore heatmap uses full range", () => {
     );
   });
 });
+
+describe("AnalyticsStore.setProject", () => {
+  beforeEach(() => {
+    resetStore();
+    vi.clearAllMocks();
+    mockAllAPIs();
+  });
+
+  it("should toggle project on first click", () => {
+    analytics.setProject("alpha");
+    expect(analytics.project).toBe("alpha");
+  });
+
+  it("should clear project when clicking same project", () => {
+    analytics.setProject("alpha");
+    analytics.setProject("alpha");
+    expect(analytics.project).toBe("");
+  });
+
+  it("should switch to different project", () => {
+    analytics.setProject("alpha");
+    analytics.setProject("beta");
+    expect(analytics.project).toBe("beta");
+  });
+
+  it("should include project in filtered panel params", () => {
+    analytics.setProject("alpha");
+
+    const summaryParams =
+      vi.mocked(api.getAnalyticsSummary).mock.lastCall?.[0];
+    expect(summaryParams?.project).toBe("alpha");
+
+    const toolsParams =
+      vi.mocked(api.getAnalyticsTools).mock.lastCall?.[0];
+    expect(toolsParams?.project).toBe("alpha");
+  });
+
+  it("should exclude project from fetchProjects params", () => {
+    analytics.setProject("alpha");
+
+    const projectsParams =
+      vi.mocked(api.getAnalyticsProjects).mock.lastCall?.[0];
+    expect(projectsParams?.project).toBeUndefined();
+  });
+
+  it("should exclude project from fetchProjects even with selectedDate", () => {
+    analytics.selectDate("2024-01-15");
+    vi.clearAllMocks();
+    mockAllAPIs();
+
+    analytics.setProject("alpha");
+
+    const projectsParams =
+      vi.mocked(api.getAnalyticsProjects).mock.lastCall?.[0];
+    expect(projectsParams?.project).toBeUndefined();
+    expect(projectsParams?.from).toBe("2024-01-15");
+  });
+
+  it("should clear project param from panels after deselecting", () => {
+    analytics.setProject("alpha");
+    vi.clearAllMocks();
+    mockAllAPIs();
+
+    analytics.setProject("alpha"); // deselect
+
+    const summaryParams =
+      vi.mocked(api.getAnalyticsSummary).mock.lastCall?.[0];
+    expect(summaryParams?.project).toBeUndefined();
+  });
+});