Add Product Hunt badge to website

[Harukafly]

What changed

• Add a compact Product Hunt badge below the primary download actions.
• Link directly to Peek's scheduled Product Hunt launch page.
• Support both English and Chinese labels using the existing language switcher.
• Render the badge locally with CSS so the site keeps its no-tracking promise.

Why

Peek is scheduled to launch on Product Hunt. The badge gives website visitors a direct path to the launch page without adding third-party scripts or remote badge assets.

Validation

• Checked the page locally in both Chinese and English.
• Verified the Product Hunt URL and layout.
• Ran git diff --check.