fix(github): temporarily hide integration entry points

[Redchar1992]

Summary

• hide the GitHub connection controls in the header and Home page
• hide the Git panel from the sidebar and plugin manager
• keep all existing GitHub/Git/OAuth/token/Deno implementation unchanged

Scope

Temporary UI-only change based on the current public main / v2.3.2.

Diff: 4 files, 9 insertions, 10 deletions.

Validation

• pnpm nx run remix-ide:lint
• pnpm eslint libs/remix-ui/top-header/src/lib/top-header.js
• NODE_OPTIONS=--max-old-space-size=6144 pnpm build:prod

No merge or deployment has been performed.

[Redchar1992]

CI update: Build passed. The non-blocking Lint job stopped in pnpm audit --prod before linting because the unchanged v2.3.2 dependency graph now reports 7 upstream advisories (brace-expansion, Mermaid, and DOMPurify). This PR does not change dependencies; local pnpm lint:libs and pnpm nx lint remix-ui-file-explorer both passed.

[Redchar1992]

Superseded by #7 after renaming the head branch to the neutral fix/ prefix.