feat: add color differentiation for actual/expected values in test failures

[Copilot]

Test failure output shows actual and expected values in the same color, making mismatches hard to spot:

Expected 'aaba' to equal specified value: 'ba'

Changes

• Parse lab failure output to extract actual/expected values from multiple @hapi/code assertion patterns:
  • Expected <actual> to equal specified value: <expected>
  • Expected <actual> to include <expected>
  • Expected <actual> to contain <expected> (displays as "include")
• Set TestMessage properties actualOutput and expectedOutput to trigger VS Code's native diff view with red/green highlighting
• Handle edge cases including quote removal (only paired quotes), ANSI stripping, and non-comparison errors

Implementation

Added FailureInfo interface and enhanced parseErrorMessage():

interface FailureInfo {
  message: string;
  actualOutput?: string;
  expectedOutput?: string;
}

const testMessage = new vscode.TestMessage(failureInfo.message);
if (failureInfo.actualOutput && failureInfo.expectedOutput) {
  testMessage.actualOutput = failureInfo.actualOutput;
  testMessage.expectedOutput = failureInfo.expectedOutput;
}

Applies to inline editor decorations, Test Explorer tooltips, and the Test Results panel.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>No colour differentiation for actual/expected values in test failure output</issue_title>
<issue_description>When a test fails due to an expectation mismatch, the actual and expected values are displayed without colour differentiation, making them hard to distinguish at a glance.

Current behaviour

Failure output shows:
```
actual expected

'aaba'

Expected 'aa' to equal specified value: 'ba'
```
All text appears in the same colour.

Suggested behaviour

Apply colour coding to differentiate:

• Actual value (e.g., red)
• Expected value (e.g., green)

This should apply to:

1. The inline failure message in the editor
2. The tooltip next to the test name

---

Feedback from Kevin Paxton</issue_description>

<agent_instructions>ensure commits are in semantic release format</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes No colour differentiation for actual/expected values in test failure output #35

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[mtharrison]

@copilot I would like to see colour coded comparison between expected and actual assertion in the tooltip next to the test name

[Copilot]

@copilot I would like to see colour code...

Updated the regex pattern in commit 81c4dc6 to support "to include" and "to contain" assertions in addition to "to equal".

The extension now extracts actual and expected values from assertions like:

• Expected { a: 1 } to include { b: 1 }
• Expected 'hello' to include 'world'
• Expected 'foo' to equal specified value: 'bar'

When both actualOutput and expectedOutput are set on the TestMessage, VS Code automatically displays them in a color-coded diff view (red for actual, green for expected) in the tooltip next to the test name, inline editor decorations, and the Test Results panel.