fix(FN-2396): align directory picker select button styling

- Switch the DirectoryPicker Select action to shared btn btn-primary classes with explicit button type
- Move select-button padding to component-scoped DirectoryPicker.css tokens and remove hardcoded !important overrides
- Extend DirectoryPicker tests to assert the expected class contract before click behavior

packages/dashboard/app/components/DirectoryPicker.css

@@ -214,7 +214,5 @@
 
 .directory-picker-select-btn {
   flex-shrink: 0;
-  padding: 6px 16px !important;
-  font-size: 13px !important;
+  padding: var(--space-sm) var(--space-lg);
 }
-

packages/dashboard/app/components/DirectoryPicker.tsx

@@ -1,7 +1,7 @@
-import "./DirectoryPicker.css";
 import { useState, useCallback, useEffect } from "react";
 import { Folder, FolderOpen, ChevronRight, ChevronUp, Loader2, Eye, EyeOff, AlertCircle } from "lucide-react";
 import { browseDirectory, type BrowseDirectoryResult } from "../api";
+import "./DirectoryPicker.css";
 
 export interface DirectoryPickerProps {
   value: string;
@@ -218,7 +218,8 @@ export function DirectoryPicker({ value, onChange, placeholder, onInputKeyDown,
               {browser.currentPath}
             </span>
             <button
-              className="btn-primary directory-picker-select-btn"
+              type="button"
+              className="btn btn-primary directory-picker-select-btn"
               onClick={handleSelect}
             >
               Select

packages/dashboard/app/components/__tests__/DirectoryPicker.test.tsx

@@ -116,7 +116,12 @@ describe("DirectoryPicker", () => {
       expect(screen.getByText("projects")).toBeDefined();
     });
 
-    fireEvent.click(screen.getByText("Select"));
+    const selectButton = screen.getByRole("button", { name: "Select" });
+    expect(selectButton.classList.contains("btn")).toBe(true);
+    expect(selectButton.classList.contains("btn-primary")).toBe(true);
+    expect(selectButton.classList.contains("directory-picker-select-btn")).toBe(true);
+
+    fireEvent.click(selectButton);
     expect(onChange).toHaveBeenCalledWith("/home/user");
   });