[Feature]: Add Changed files context menu actions

[adinvadim]

Before submitting

• I searched existing issues and did not find a duplicate.
• I am describing a concrete problem or use case, not just a vague idea.

Area

apps/web

Problem or use case

The Changed files section is useful for quickly reviewing what a turn touched, but file-level actions there are currently limited. Left click opens the diff, which is good, but there is no direct right-click workflow for common file actions.

When I am reviewing changed files, I often want to copy a file path into the composer or open that exact file in an editor without switching to another panel or manually selecting text.

Proposed solution

Add a context menu for file rows in Changed files.

Suggested actions:

• Copy path: copy the displayed relative file path.
• Open with...: open the selected file using the existing editor/open-with infrastructure.

Behavior details:

• Keep the current left-click behavior: clicking a file still opens the turn diff focused on that file.
• Scope the menu to file rows first. Directory rows can keep their current expand/collapse behavior.
• Reuse existing local context menu and editor-opening paths where possible, instead of adding a separate file-action system.
• If only one editor/preferred editor is available, Open with... can fall back to opening directly or use the same picker used elsewhere in the app.

Why this matters

This makes the Changed files section a faster review and follow-up surface. It reduces friction when asking the agent about a specific file, checking the implementation in an editor, or copying a changed path for another tool.

Smallest useful scope

A first pass can be limited to file rows in ChangedFilesTree:

• right-click menu on file rows only
• copy relative path
• open file through the existing preferred editor/open-with flow
• no changes to directory rows, diff rendering, or server contracts

Alternatives considered

A visible copy button in diff headers would also help, and there is an existing related PR for that. A context menu keeps the Changed files tree compact and puts file actions where the file is listed.

Manual selection and copy works today, but it is slow and error-prone for long paths.

Risks or tradeoffs

The main risk is adding too much UI surface to a compact list. Keeping this behind right-click and reusing existing context menu primitives should keep the change small.

The menu should also avoid interfering with the existing left-click diff navigation.

Examples or references

Related:

• feat(web): add copy path button to diff headers #2403
• Make open button configurable #433

Existing comparable behavior: markdown file links already expose context-menu actions such as opening in editor and copying paths.

Contribution

• I would be open to helping implement this.

I am ready to implement this quickly if the proposed scope looks acceptable.