perf(linter): Implement streaming diagnostics for tsgolint instead of waiting for output to finish

[Copilot]

This PR resolves the TODO comment at line 126 in apps/oxlint/src/tsgolint.rs by implementing streaming diagnostics for tsgolint instead of waiting for the entire process to complete.

Problem

Previously, the tsgolint integration would:

1. Spawn the tsgolint process
2. Wait for the entire process to complete using child.wait_with_output()
3. Parse all output at once
4. Send all diagnostics to the diagnostic service

This approach meant users had to wait for tsgolint to process all files before seeing any feedback, which could be slow for large codebases.

Solution

The implementation now streams diagnostics as they are emitted:

1. Streaming stdout reader: Reads from the tsgolint process stdout in 4KB chunks as data becomes available
2. Incremental message parsing: Uses the existing binary protocol parser to process complete messages as they arrive in the buffer
3. Immediate diagnostic sending: Sends diagnostics to the diagnostic service via the error_sender channel as soon as they are parsed
4. Proper buffering: Keeps incomplete messages in the buffer for the next iteration to handle message boundaries correctly

Key Changes

• Replaced child.wait_with_output() with streaming stdout reading in a separate thread
• Added incremental buffer processing that identifies complete messages using the binary protocol format
• Maintained backward compatibility - all existing tests pass
• Removed unused parse_tsgolint_output() function since parsing now happens incrementally
• Added proper error handling for both process exit status and stdout processing

Benefits

• Faster feedback: Users see diagnostics as soon as tsgolint emits them, rather than waiting for completion
• Better user experience: Especially beneficial for large codebases where tsgolint processing takes significant time
• Same reliability: All existing functionality and error handling is preserved
• No breaking changes: The API and behavior remain the same from the user's perspective

The streaming implementation provides a more responsive experience while maintaining full compatibility with existing tsgolint integration.

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.

[graphite-app]

How to use the Graphite Merge Queue

Add either label to this PR to merge it via the merge queue:

• 0-merge - adds this PR to the back of the merge queue
• hotfix - for urgent hot fixes, skip the queue and merge this PR next

You must have a Graphite account in order to use the merge queue. Sign up using this link.

An organization admin has enabled the Graphite Merge Queue in this repository.

Please do not merge from GitHub as this will restart CI on PRs being processed by the merge queue.

[Copilot]

Pull Request Overview

This PR implements streaming diagnostics for the tsgolint integration, allowing users to see diagnostics as they are emitted rather than waiting for the entire process to complete. This addresses the TODO comment and improves responsiveness for large codebases.

• Replaces blocking wait_with_output() with streaming stdout reading in a separate thread
• Implements incremental message parsing using existing binary protocol parser
• Maintains backward compatibility while providing faster user feedback

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.
You can also share your feedback on Copilot code review for a chance to win a $100 gift card. Take the survey.}

[Boshen]

Merge activity

• Aug 15, 9:07 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Aug 15, 9:07 AM UTC: Boshen added this pull request to the Graphite merge queue.
• Aug 15, 9:13 AM UTC: Merged by the Graphite merge queue.