Ignore timestamp update errors like in strada

[sheetalkamat]

Fixes #1664

[Copilot]

Pull Request Overview

This PR ignores timestamp update errors in the TypeScript build process, similar to how it's handled in strada. Instead of reporting diagnostic errors when file timestamp updates fail, the code now silently continues with execution.

Key Changes

• Remove error reporting for timestamp update failures
• Reorganize logic to only execute additional operations when timestamp updates succeed
• Update test baselines to remove the timestamp update error message

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
internal/execute/build/buildtask.go	Modified to skip error reporting when SetMTime fails and restructured conditional logic
internal/diagnostics/extraDiagnosticMessages.json	Removed the "Failed to update timestamp" diagnostic message definition
internal/diagnostics/diagnostics_generated.go	Updated generated diagnostics to replace the removed message with a different one
internal/execute/tsctests/tscbuild_test.go	Added new test cases for project reference scenarios
Test baseline files	Updated to remove timestamp update error messages from expected outputs