Amazon Q: Integrate VS Code Diagnostics API to Auto-detect Editor Errors

## Problem
Amazon Q Developer VS Code extension currently cannot automatically detect errors displayed in the editor. Instead, it relies on build results to identify issues, which:
- Takes unnecessary time waiting for builds to complete
- Frequently interrupts workflow with command execution permission prompts
- Creates a disjointed experience when trying to fix simple syntax or typing errors

Other coding agents like Cline already demonstrate this capability to immediately recognize and assist with errors as they appear in the editor without requiring build steps.

## Expected behavior
- Amazon Q Developer should integrate with VS Code's languages.getDiagnostics() API
- The extension should automatically detect and recognize errors/warnings shown in the editor
- It should offer assistance for fixing these issues without requiring builds
- Similar to Cline, it should be able to see the same diagnostic information that appears in the editor's Problems panel

The issue names no files or tests. Start by locating the Amazon Q VS Code extension's existing build-result error handling, then review VS Code's languages.getDiagnostics() API and the Problems panel behavior. Done means editor diagnostics are detected and assistance can be offered without waiting for a build.

Written by the indexing model from the issue text.