fix: Open project dialog shows 'No folders found' in web UI

[lxxonx]

Bug Description

The "Open project" dialog in the web UI shows "No folders found" instead of listing directories.

Root Causes

1. Server API issue: /find/file endpoint requires query parameter, but the SDK sends empty string as undefined, resulting in 400 Bad Request
2. Server API issue: directory parameter is ignored - always searches current project directory instead of the specified home directory
3. UI Hook issue: useFilteredList hook doesn't properly handle async items function with filter parameter

Steps to Reproduce

1. Run opencode web
2. Open the web UI in browser
3. Press Cmd+O or click "Open project"
4. Dialog shows "No folders found"

Expected Behavior

Dialog should list directories from the home folder.

Environment

• Version: 1.1.19
• Platform: macOS / Web UI