Fix bugs in loader parsers

[obiot]

Summary

• script.js: Fix undefined crossOrigin variable reference — was checking an undeclared variable instead of settings.crossOrigin
• video.js: Fix unsafe regex match on data URLs (null check), fix missing error parameter in videoElement.onerror callback, normalize import path
• fontface.js: Fix missing error parameter in font.load() rejection handler, fix JSDoc example syntax

Test plan

• All 1921 tests pass
• New tests: onerror callbacks for invalid image/JSON/binary sources
• New test: inline TMX data returns correct resource count

🤖 Generated with Claude Code

[Copilot]

Pull request overview

This PR fixes several correctness issues in the asset loader parser implementations, improving error propagation and handling of edge cases (notably data URLs), and adds regression tests to ensure loader error callbacks fire reliably.

Changes:

• Fix script parser CORS handling by using settings.crossOrigin (instead of an undeclared variable).
• Harden video parser data URL MIME parsing (null-safe) and pass the event/error argument through videoElement.onerror.
• Fix fontface parser rejection handler to forward the rejection error and correct a broken JSDoc example.
• Add loader tests covering onerror behavior for invalid sources and inline TMX resource counting.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
packages/melonjs/tests/loader.spec.js	Adds regression tests for onerror callbacks (image/json/binary) and inline TMX load() return count.
packages/melonjs/src/loader/parsers/video.js	Normalizes import path, avoids unsafe regex match access for data URLs, and forwards the onerror argument.
packages/melonjs/src/loader/parsers/script.js	Correctly applies crossOrigin from loader-provided settings.
packages/melonjs/src/loader/parsers/fontface.js	Forwards the actual font loading rejection error to onerror and fixes invalid JSDoc example syntax.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.