[General] Allow faster copy path for files referenced by agent

### Feature summary

When an agent references a file it is hard to get the path

### What problem are you trying to solve?

When the agent references some lines in a file clicking it opens a viewer in the review panel however there is not an easy way to see the path or copy it. The fastest path I see is opening the file in the viewer then clicking the folder view then right clicking the correct file to "copy path".

### Proposed solution

Add an option to either right click the file name at the top of the review panel or in the file viewer have a top banner with the full path that can be copied.

### Workflow impact

When there are small issues that are easier to fix via a code editor than getting the agent to fix it having quick access to the file path eases the flow.

### Installation context

_No response_

### Additional context

_No response_

Start by locating the review panel and file viewer components described in the issue, then trace how referenced files are opened. Done means a user can quickly view and copy the full file path from one of the proposed locations; verify the interaction in the desktop app.

索引モデルが issue の本文から書いたものです。