feat(directory-browser): add custom dialog for project and folder select

- Add DirectoryBrowserDialog component with breadcrumb navigation, filtering, and keyboard shortcuts
- Implement browseDirectories server endpoint for listing directory contents
- Replace native picker with custom dialog in add project and add folder flows
- Add addProjectBaseDirectory setting to remember last project path
- Simplify Sidebar state management by consolidating add-project logic
- Support keyboard shortcuts (↑/↓ to navigate, Enter to select, Backspace/Cmd+Enter for navigation)
- Add integration guard test for directory browser

Author: tyulyukov

apps/server/src/serverSettings.test.ts

@@ -209,6 +209,24 @@ it.layer(NodeServices.layer)("server settings", (it) => {
     }).pipe(Effect.provide(makeServerSettingsLayer())),
   );
 
+  it.effect("round-trips addProjectBaseDirectory through patch + decode", () =>
+    Effect.gen(function* () {
+      const serverSettings = yield* ServerSettingsService;
+
+      const next = yield* serverSettings.updateSettings({
+        addProjectBaseDirectory: "/Users/tester/Projects",
+      });
+
+      assert.equal(next.addProjectBaseDirectory, "/Users/tester/Projects");
+
+      const followup = yield* serverSettings.updateSettings({
+        addProjectBaseDirectory: "A",
+      });
+
+      assert.equal(followup.addProjectBaseDirectory, "A");
+    }).pipe(Effect.provide(makeServerSettingsLayer())),
+  );
+
   it.effect("writes only non-default server settings to disk", () =>
     Effect.gen(function* () {
       const serverSettings = yield* ServerSettingsService;

apps/server/src/workspaceEntries.test.ts

@@ -6,7 +6,7 @@ import { spawnSync } from "node:child_process";
 
 import { afterEach, assert, describe, it, vi } from "vitest";
 
-import { searchWorkspaceEntries } from "./workspaceEntries";
+import { browseDirectories, searchWorkspaceEntries } from "./workspaceEntries";
 
 const tempDirs: string[] = [];
 
@@ -200,3 +200,80 @@ describe("searchWorkspaceEntries", () => {
     assert.isAtMost(peakReads, 32);
   });
 });
+
+describe("browseDirectories", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+    for (const dir of tempDirs.splice(0, tempDirs.length)) {
+      fs.rmSync(dir, { recursive: true, force: true });
+    }
+  });
+
+  it("returns directory entries relative to cwd with resolvedParent", async () => {
+    const cwd = makeTempDir("marcode-browse-basic-");
+    fs.mkdirSync(path.join(cwd, "alpha"));
+    fs.mkdirSync(path.join(cwd, "beta"));
+    writeFile(cwd, "readme.md", "");
+
+    const result = await browseDirectories({ cwd, pathQuery: "", limit: 100 });
+    const names = result.entries.map((entry) => entry.path);
+
+    assert.sameMembers(names, ["alpha", "beta"]);
+    assert.equal(result.resolvedParent, path.resolve(cwd));
+    assert.isFalse(result.truncated);
+  });
+
+  it("resolves absolute paths in pathQuery regardless of cwd", async () => {
+    const cwd = makeTempDir("marcode-browse-cwd-");
+    const other = makeTempDir("marcode-browse-abs-");
+    fs.mkdirSync(path.join(other, "nested"));
+
+    const result = await browseDirectories({ cwd, pathQuery: `${other}/`, limit: 100 });
+    const names = result.entries.map((entry) => entry.path);
+
+    assert.equal(result.resolvedParent, path.resolve(other));
+    assert.include(
+      names.map((name) => path.basename(name)),
+      "nested",
+    );
+  });
+
+  it("expands ~/ in cwd to the user's home directory", async () => {
+    const homeDir = os.homedir();
+    const sentinel = `marcode-browse-home-sentinel-${process.pid}-${Date.now()}`;
+    const sentinelPath = path.join(homeDir, sentinel);
+    fs.mkdirSync(sentinelPath);
+    try {
+      const result = await browseDirectories({ cwd: "~/", pathQuery: "", limit: 100 });
+
+      assert.equal(result.resolvedParent, path.resolve(homeDir));
+      assert.isTrue(result.entries.some((entry) => path.basename(entry.path) === sentinel));
+    } finally {
+      fs.rmSync(sentinelPath, { recursive: true, force: true });
+    }
+  });
+
+  it("resolves ../ relative to cwd", async () => {
+    const parent = makeTempDir("marcode-browse-parent-");
+    const child = path.join(parent, "child");
+    fs.mkdirSync(child);
+    fs.mkdirSync(path.join(parent, "sibling"));
+
+    const result = await browseDirectories({ cwd: child, pathQuery: "../", limit: 100 });
+
+    assert.equal(result.resolvedParent, path.resolve(parent));
+    const names = result.entries.map((entry) => path.basename(entry.path));
+    assert.includeMembers(names, ["child", "sibling"]);
+  });
+
+  it("returns empty entries and resolvedParent when directory does not exist", async () => {
+    const cwd = makeTempDir("marcode-browse-missing-");
+    const missing = path.join(cwd, "does-not-exist");
+
+    const result = await browseDirectories({ cwd: missing, pathQuery: "", limit: 100 });
+
+    assert.deepEqual([...result.entries], []);
+    assert.equal(result.resolvedParent, path.resolve(missing));
+    assert.isFalse(result.truncated);
+  });
+});

apps/server/src/workspaceEntries.ts

@@ -1,5 +1,6 @@
 import fs from "node:fs/promises";
 import type { Dirent } from "node:fs";
+import os from "node:os";
 import path from "node:path";
 import { runProcess } from "./processRunner";
 
@@ -580,19 +581,29 @@ function parsePathQueryComponents(pathQuery: string): { parentDir: string; nameP
   };
 }
 
+function expandHomePath(value: string): string {
+  if (value === "~") return os.homedir();
+  if (value.startsWith("~/") || value.startsWith("~\\")) {
+    return path.join(os.homedir(), value.slice(2));
+  }
+  return value;
+}
+
 export async function browseDirectories(
   input: ProjectBrowseDirectoriesInput,
 ): Promise<ProjectBrowseDirectoriesResult> {
-  const { parentDir, namePrefix } = parsePathQueryComponents(input.pathQuery);
-  const resolvedParent = path.resolve(input.cwd, parentDir);
+  const expandedCwd = expandHomePath(input.cwd);
+  const expandedPathQuery = expandHomePath(input.pathQuery);
+  const { parentDir, namePrefix } = parsePathQueryComponents(expandedPathQuery);
+  const resolvedParent = path.resolve(expandedCwd, parentDir);
   const limit = Math.max(0, Math.floor(input.limit));
   const lowerPrefix = namePrefix.toLowerCase();
 
   let dirents: Dirent[];
   try {
     dirents = await fs.readdir(resolvedParent, { withFileTypes: true });
   } catch {
-    return { entries: [], truncated: false };
+    return { entries: [], truncated: false, resolvedParent };
   }
 
   dirents.sort((a, b) => a.name.localeCompare(b.name));
@@ -627,5 +638,5 @@ export async function browseDirectories(
     });
   }
 
-  return { entries, truncated };
+  return { entries, truncated, resolvedParent };
 }

apps/web/src/components/ChatView.tsx

@@ -5171,6 +5171,8 @@ export default function ChatView({ threadId, environmentId: environmentIdProp }:
                       >
                         <ComposerAttachmentsPopover
                           threadId={activeThread.id}
+                          environmentId={activeThreadEnvironmentId ?? null}
+                          projectCwd={activeProjectCwd}
                           additionalDirectories={activeThread.additionalDirectories}
                           onLocalDirectoriesChange={
                             isLocalDraftThread ? setDraftAdditionalDirectories : undefined