fix(site): mobile landing preview scale and tentacle layout

[Tam-Leal]

Summary

Fixes the landing page product preview on mobile: the full dashboard screenshot stays visible at proportional scale, horizontal scroll is removed, and tentacle placement is tuned for small screens without changing desktop layout or image assets.

Type of change

• Documentation / site only

What changed

• site/index.html: .preview-stage wrapper; mobile @media uses single zoom scale (with transform fallback); per-tentacle tweaks only where needed (left pair, front pair, right tentacle).
• site/css/index.css: .preview-stage desktop wrapper; removed dead per-tentacle rules that never applied (inline CSS wins); mobile overflow-x: clip on preview/html/body.
• .gitattributes: text=auto eol=lf so Windows/Cursor do not flip line endings on every save.

Release

No GitHub Release or version bump. Site-only change (redeploy site/ when you publish the site).

Checklist

• Site-only — npm test not required for this PR
• Smoke-tested preview at http://localhost:3848/ (desktop + mobile ~390px)
• No secrets in commits
• Updated CHANGELOG.md under Unreleased

Test plan

• Desktop (~1280px): preview matches pre-change layout; tentacles and dashboard unchanged
• Mobile (390px): full dashboard visible, no horizontal scroll
• Tentacles: left pair separated; front pair sized/spaced; right tentacle lower, behind dashboard
• After deploy: spot-check https://www.gitdock.dev/ on phone or DevTools