User/kendzisah/fix manifest analyzer validation

[kendzisah10]

fixes #[issue number]
#5119

PR Type

• Bugfix

Describe the current behavior?

Previous Behavior and Bug

The Problem: PWABuilder's manifest analysis was insufficient, allowing invalid manifests to pass validation and subsequently fail during packaging. Specifically:

• Missing image validation: Existing CheckImagesAreFetchable method existed but wasn't comprehensive enough
• No type consistency checking: Existing type check wasn't truly checking the type of the image- only checking if the image had a type specified.
• No size validation: Didn't correctly validate all sizes.

Describe the new behavior?

The Solution: Implemented comprehensive image validation with multiple new capability checks:

• Enhanced type validation
• New size validation
• Improved type consistency
• Fixed Early Error Detection so errors are caught before packaging.

PR Checklist

• Test: run npm run test and ensure that all tests pass
• Target main branch (or an appropriate release branch if appropriate for a bug fix)
• Ensure that your contribution follows standard accessibility guidelines. Use tools like https://webhint.io/ to validate your changes.

Additional Information

[Copilot]

Pull Request Overview

This PR enhances PWABuilder's manifest validation by implementing comprehensive image validation for icons and screenshots. The changes address a critical gap where invalid manifests were passing validation and subsequently failing during packaging.

• Added new capability checks for validating icon and screenshot types match their actual file types
• Added new capability checks for validating declared sizes match actual image dimensions
• Enhanced existing icon type checking logic to validate both declared types and file extensions consistently

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
ManifestAnalyzer.cs	Added new capability checks and improved icon type validation logic
ImageValidationService.cs	Added new validation methods for image types and dimensions using ImageSharp
PwaCapabilityId.cs	Added enum values for the new validation capabilities
PwaCapability.cs	Added capability definitions for the new validation checks

[kendzisah10]

Screenshot of the analyzer in effect: