Add execution marker for command execution tracking

[daniel-lxs]

Closes: #4200
Closes: #4384

This PR implements a marker to track when a command finished executing as a workaround for this VSCode issue: microsoft/vscode#250764.

The inspiration comes from @sstublic's comment: #4200 (comment)

Basically commands executed by Roo Code will look like this on the terminal:

git commit -m "this is a commit" ; echo -n "ROO_CMD_1749668438357_9frv9vg"

Then we check if the marker is present in the output, this is completely hidden from the model to avoid confusion.

I tested against the integrations tests that were failing due to the bug and it solved the issues.
Also tested on Windows.

---

Important

Adds execution marker in TerminalProcess to track command completion by appending and detecting a unique marker in command output.

• Behavior:
  • Adds executionMarker to TerminalProcess to track command completion.
  • Appends unique marker to commands in run() to detect completion in output stream.
  • Handles both PowerShell and other shells by appending marker differently.
• Execution:
  • Detects marker in output stream to determine command completion.
  • Removes marker from fullOutput once detected.
  • Emits shell_execution_complete event with success exit code if marker is detected.
• Misc:
  • Updates run() to handle marker logic and stream processing.
  • Adds comments explaining marker usage and stream handling.

^{This description was created by for 7b8dde8. You can customize this summary. It will automatically update as commits are pushed.}

[daniel-lxs]

Closing this for now.

[mrubens]

What do you think of a version of this where we do it for Powershell only if that’s the most acute issue and then roll it out to other shells as a follow-up once it’s live for a bit? cc: @sstublic

[sstublic]

What do you think of a version of this where we do it for Powershell only if that’s the most acute issue and then roll it out to other shells as a follow-up once it’s live for a bit? cc: @sstublic

Since there are no other takes on this and @daniel-lxs seems to have done a really good job with this, I'd be really happy and grateful with any progress on the issue.

From my end, if you do this for Powershell, I'll use it for sure and leave a feedback if it's working correctly/bug is fixed. Maybe you can use that to decide if you want to move on to other shells.

[daniel-lxs]

We can probably make it so that this is enabled with a setting in the Terminal section, that way users that are affected can be instructed to enable this.

If we hear reports that this implementation is affecting them in any other way we can either remove it or polish it