[FEATURE] Desktop app: @ file mention should match partial paths like @create/form.vue

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

In the Claude Code desktop app (macOS), the @ file mention picker returns no results when the query includes part of a path. Many projects have files with the same name in several feature folders, such as:

- src/features/orders/create/form.vue
- src/features/orders/edit/form.vue
- src/features/customers/create/form.vue
- src/features/customers/edit/form.vue

Typing @create/form.vue should narrow the list to the create forms. Instead, the picker shows no results, and searching for form.vue alone returns too many similar files.

Proposed Solution

When the query contains /, match each part against path segments in order, with the last part matching the file name. create/form.vue, /create/form and orders/create/form should all resolve.

VS Code quick open and fzf already match paths this way.

Alternative Solutions

Typing the full path from the project root, or copying it from the file tree.

Priority

High - Significant impact on productivity

Feature Category

File operations

Use Case Example

_No response_

Additional Context

This may be related to #94204: desktop @ mentions miss files nested more than 3 folders deep.