Code review: packaging and test coverage findings

Problem/Motivation

A code review of this module turned up a few packaging and test-coverage items worth addressing. Nothing here is a functional bug; the module works correctly as shipped.

1. Missing .gitignore | Severity: Minor | File: project root
   
   There is no .gitignore file at all. At minimum it should ignore .DS_Store (and any local IDE files).
2. composer.json missing an "authors" section | Severity: Minor | File: composer.json
   
   composer.json has "support" (issues/source) but no "authors" entry listing the maintainer(s) with name, drupal.org profile URL and role, which is the convention documented in drupal.org packaging guidelines.
3. Missing test coverage for the broken Media type fallback path | Severity: Minor | File: src/Hook/RemoteVideoShapeMatchingHooks.php
   
   getSourceFieldDefinition() catches PluginException/InvalidArgumentException/LogicException and logs a warning so a broken Media type does not break shape matching site-wide, but RemoteVideoShapeMatchingTest.php has no test exercising that catch branch (e.g. a Media type whose source field was removed after creation). Worth adding a kernel test for it since it is the one piece of defensive logic in the module.

Proposed resolution

• Add a .gitignore with .DS_Store.
• Add an "authors" section to composer.json.
• Add a kernel test covering the exception-handling branch in getSourceFieldDefinition().

AI was used to investigate and for better solutions. The issues were then manually reviewed/tested.