Fix public share comments response handling

[GChaucer]

Summary

• Normalize public share comments responses on the single-asset share page
• Support both the current bare array response and { comments: [...] } fallback shape
• Keep behavior aligned with the folder share viewer

Fixes #67

Testing

• corepack pnpm install --frozen-lockfile --ignore-scripts
• corepack pnpm exec tsc --noEmit
• corepack pnpm exec eslint 'app/share/[token]/page.tsx'

[ravirajsinh45]

LGTM — minimal, well-scoped fix that correctly handles both response shapes the API returns. Backend inconsistency at comments.py:557 vs :567 is the real root cause; worth a follow-up to normalize, but the frontend handling here is defensive and correct.