fix(lint): allow producer-resolved Google Fonts

[miguel-heygen]

Summary

• demote google_fonts_import from error to warning so EF/Zephyr workspaces are not blocked before producer-side font resolution can run
• treat families explicitly loaded by Google Fonts URLs as externally resolvable for font_family_without_font_face
• parse quoted/unquoted <link> hrefs, @import URLs, multiple family= params, and URL-encoded family names

Why

Producer already resolves Google Fonts during compile/render. The hard lint error moved the failure boundary before producer could canonicalize fonts, causing Zephyr retry loops. We still warn on raw Google Fonts imports because mapped/local fonts are preferred, but they no longer fail lint when producer can resolve them.

Tests

• bun test packages/core/src/lint/rules/fonts.test.ts
• bunx oxlint packages/core/src/lint/rules/fonts.ts packages/core/src/lint/rules/fonts.test.ts
• bunx oxfmt --check packages/core/src/lint/rules/fonts.ts packages/core/src/lint/rules/fonts.test.ts
• bun run --filter @hyperframes/core test (after bun run --filter @hyperframes/core build:hyperframes-runtime)