[Feature]: Add “Reveal in Finder” and native actions for local file links

[sprintthunder-dotcom]

Description

When an agent creates a local file and returns a clickable file link in the chat, T3 Code recognizes it as a local t3code://app/... path.

However, on macOS there is no convenient way to locate or open that generated file outside T3 Code.

The file link does not provide actions such as:

• Reveal in Finder
• Open with the default macOS application
• Copy absolute file path

This is especially inconvenient for generated artifacts such as .txt, .csv, .xlsx, .pdf, and images that need to be uploaded or used in another application.

Steps to reproduce

1. Ask an agent to create a file, for example ~/Downloads/example.txt.
2. Have the agent return a clickable Markdown link to that file.
3. Click, double-click, or right-click the file link in the T3 Code conversation.
4. Observe that there is no "Reveal in Finder" or equivalent native file action.

Current behavior

The link is handled as an internal t3code://app/<absolute-path> link, but the user cannot easily locate the file in Finder.

Expected behavior

For valid local file links, provide a context menu containing:

• Reveal in Finder / Show in Folder
• Open with Default Application
• Copy Absolute Path

Suggested interaction:

• Single click: keep the existing internal preview/open behavior.
• Double-click: open the file with the operating system's default application.
• Right-click: show the native file-action menu.

These actions should also work for agent-generated files located outside the current repository, such as files in ~/Downloads.

For remote sessions, the actions could be disabled or adapted when the file is not on the desktop client's local filesystem.

Environment

• T3 Code Alpha: 0.0.31
• macOS: 27.0 (Build 26A5388g)
• T3 Code bundle: com.t3tools.t3code