refactor(workbench): simplify URL handling and improve PortDropdown UI

- Replace `url` state with `displayPath` in Preview component to focus on path handling
- Update PortDropdown to display active port and improve styling
- Remove redundant URL validation logic

app/components/workbench/PortDropdown.tsx

@@ -1,5 +1,4 @@
 import { memo, useEffect, useRef } from 'react';
-import { IconButton } from '~/components/ui/IconButton';
 import type { PreviewInfo } from '~/lib/stores/previews';
 
 interface PortDropdownProps {
@@ -48,9 +47,18 @@ export const PortDropdown = memo(
 
     return (
       <div className="relative z-port-dropdown" ref={dropdownRef}>
-        <IconButton icon="i-ph:plug" onClick={() => setIsDropdownOpen(!isDropdownOpen)} />
+        {/* Display the active port if available, otherwise show the plug icon */}
+        <button
+          className="flex items-center group-focus-within:text-bolt-elements-preview-addressBar-text bg-white group-focus-within:bg-bolt-elements-preview-addressBar-background dark:bg-bolt-elements-preview-addressBar-backgroundHover rounded-full px-2 py-1 gap-1.5"
+          onClick={() => setIsDropdownOpen(!isDropdownOpen)}
+        >
+          <span className="i-ph:plug text-base"></span>
+          {previews.length > 0 && activePreviewIndex >= 0 && activePreviewIndex < previews.length ? (
+            <span className="text-xs font-medium">{previews[activePreviewIndex].port}</span>
+          ) : null}
+        </button>
         {isDropdownOpen && (
-          <div className="absolute right-0 mt-2 bg-bolt-elements-background-depth-2 border border-bolt-elements-borderColor rounded shadow-sm min-w-[140px] dropdown-animation">
+          <div className="absolute left-0 mt-2 bg-bolt-elements-background-depth-2 border border-bolt-elements-borderColor rounded shadow-sm min-w-[140px] dropdown-animation">
             <div className="px-4 py-2 border-b border-bolt-elements-borderColor text-sm font-semibold text-bolt-elements-textPrimary">
               Ports
             </div>