Frontend: Dynamic VCS provider in code reference badges

[emyller]

Context: #7000
Depends on: #7134

The feature-list badges are hardcoded to show the GitHub icon regardless of the actual provider.

Scope

Use the vcs_provider returned by the API (added in #7134) to show the correct icon per repository.

Changes

frontend/common/types/responses.ts (~line 633): Add vcs_provider: VCSProvider to the code_references_counts type.

Three locations hardcode vcsProvider={VCSProvider.GITHUB}:

• frontend/web/components/feature-summary/FeatureTags.tsx (line 79)
• frontend/web/components/feature-summary/ProjectFeatureRow.tsx (lines 70, 119)

Replace with dynamic provider from the data. When a feature is scanned from multiple providers, show one badge per provider. Consider extracting a shared component to avoid duplicating the grouping logic.

VCSProviderTag and GitlabIcon already exist and handle GitLab — no new UI components needed.

Acceptance criteria

• Correct icon (GitHub/GitLab) shown per repository's provider
• Features scanned by both providers show both icons
• No hardcoded VCSProvider.GITHUB in badge rendering
• npm run typecheck && npm run lint pass