fix(security): remplacer base64-img

[lowzonenose]

Remplacer base64-img par une lecture/encodage natif pour améliorer la sécurité

cf. issue #447

L'encodage base64 est réalisé via la commande : npm run publish

Elle permet de convertir les images en base64 dans les CSS.

Comment tester ?

• builder et publier les extensions
• voir si des images ne sont pas cassées (ex. dans cartes.gouv.fr ou les projets demos)

[Copilot]

Pull request overview

This PR replaces the base64-img package with native Node.js file reading and base64 encoding to improve security, addressing issue #447.

Changes:

• Removed the base64-img dependency from package.json
• Implemented native base64 encoding using Node.js fs and Buffer APIs in the build script

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
package.json	Removed the base64-img dependency
build/release/package.js	Replaced base64-img.base64Sync() with native file reading and base64 encoding, including MIME type detection

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[Copilot]

The fallback MIME type 'application/octet-stream' for unsupported image formats may cause issues with CSS url() declarations. Consider either throwing an error for unsupported formats or logging a warning to alert developers when an unexpected file type is encountered.

Suggested change

	default: return 'application/octet-stream';
	default:
	console.warn(`[package] Unsupported image format '${ext}' for file '${url}'. Falling back to 'application/octet-stream'.`);
	return 'application/octet-stream';

[elias75015]

IGNF/cartes.gouv.fr-entree-carto#962 --> Pour tester côté entrée carto

OK pour moi, je n'ai rien vu de cassé