feat: filter session history by workspace directory (#11813)

* feat: filter session history by workspace directory

Add optional workspaceDirectory field to ListHistoryOptions so callers
can scope session lists to a specific workspace. Filtering is
case-insensitive and applied before pagination. Omitting the field
preserves the existing behavior of returning all sessions.

Fixes #9936

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

* fix: address bot review - typeof guard and test coverage

- Use typeof check instead of truthiness for workspaceDirectory to
  handle malformed session metadata safely
- Rename test to match actual coverage (limit only)
- Add separate test for combined limit+offset with workspace filter

---------

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: mvanhorn

core/protocol/core.ts

@@ -63,6 +63,7 @@ export enum OnboardingModes {
 export interface ListHistoryOptions {
   offset?: number;
   limit?: number;
+  workspaceDirectory?: string;
 }
 
 export type ToCoreFromIdeOrWebviewProtocol = {

core/util/history.test.ts

@@ -74,6 +74,87 @@ describe("Full session lifecycle", () => {
   });
 });
 
+describe("Workspace directory filtering", () => {
+  beforeAll(() => {
+    historyManager.clearAll();
+    historyManager.save({
+      history: [],
+      title: "Project A session 1",
+      workspaceDirectory: "/home/user/project-a",
+      sessionId: "ws-a-1",
+    });
+    historyManager.save({
+      history: [],
+      title: "Project B session 1",
+      workspaceDirectory: "/home/user/project-b",
+      sessionId: "ws-b-1",
+    });
+    historyManager.save({
+      history: [],
+      title: "Project A session 2",
+      workspaceDirectory: "/home/user/project-a",
+      sessionId: "ws-a-2",
+    });
+    historyManager.save({
+      history: [],
+      title: "No workspace",
+      workspaceDirectory: "",
+      sessionId: "ws-none",
+    });
+  });
+
+  afterAll(() => {
+    historyManager.clearAll();
+  });
+
+  test("Filter sessions by workspace directory", () => {
+    const sessions = historyManager.list({
+      workspaceDirectory: "/home/user/project-a",
+    });
+    expect(sessions.length).toBe(2);
+    expect(
+      sessions.every((s) => s.workspaceDirectory === "/home/user/project-a"),
+    ).toBe(true);
+  });
+
+  test("Omitting workspace returns all sessions", () => {
+    const sessions = historyManager.list({});
+    expect(sessions.length).toBe(4);
+  });
+
+  test("Workspace filter is case-insensitive", () => {
+    const sessions = historyManager.list({
+      workspaceDirectory: "/HOME/USER/PROJECT-A",
+    });
+    expect(sessions.length).toBe(2);
+  });
+
+  test("Non-matching workspace returns empty list", () => {
+    const sessions = historyManager.list({
+      workspaceDirectory: "/home/user/nonexistent",
+    });
+    expect(sessions.length).toBe(0);
+  });
+
+  test("Workspace filter works with limit", () => {
+    const sessions = historyManager.list({
+      workspaceDirectory: "/home/user/project-a",
+      limit: 1,
+    });
+    expect(sessions.length).toBe(1);
+  });
+
+  test("Workspace filter works with limit and offset", () => {
+    const sessions = historyManager.list({
+      workspaceDirectory: "/home/user/project-a",
+      limit: 1,
+      offset: 1,
+    });
+    expect(sessions.length).toBe(1);
+    expect(sessions[0].sessionId).toBe("ws-a-1");
+  });
+});
+
 describe("Many sessions created", () => {
   test("Create 100 sessions and list all", () => {
     for (let i = 0; i < 100; i++) {

core/util/history.ts

@@ -38,6 +38,16 @@ export class HistoryManager {
       })
       .reverse();
 
+    // Filter by workspace directory if provided
+    if (options.workspaceDirectory) {
+      const target = options.workspaceDirectory.toLowerCase();
+      sessions = sessions.filter(
+        (session) =>
+          typeof session.workspaceDirectory === "string" &&
+          session.workspaceDirectory.toLowerCase() === target,
+      );
+    }
+
     // Apply limit and offset
     if (options.limit) {
       const offset = options.offset || 0;