fix(ui): restyle Savanna tabsets to the underline tabs

[ngarakapati]

Summary

• Production doc-site still compiles AsciiDoc [tabs] with tabs-block.js (.tabset / .tab-pane).
• The Savanna theme only styled @asciidoctor/tabs (.tablist / .tabpanel), so live pages such as Connect AI tools with MCP showed the default boxed tabs.
• Restyle .tabset under .theme-cloud to the orange underline look. GSQL and other products are unchanged.

Test plan

Local production-like preview (doc-site + tabs-block.js + this bundle) on Connect AI tools with MCP:

• Tabs render as orange underline, not dark gray boxes
• Cursor is the active tab; Claude Desktop / VS Code / Claude Code stay as text labels
• After this merges, the next doc-site Netlify build picks up ui-bundle.zip and production Savanna tabs match

[Tushar-TG-14]

@ngarakapati

1. Could you confirm whether this .theme-cloud .tabset styling is also intended for Cloud Classic? Since the selector is scoped to .theme-cloud rather than Savanna specifically, this will apply to any product using the Cloud theme.

2. The current CI build is failing at Make curl call to build hook with exit code 2. Could you check whether this is an existing/infrastructure issue and rerun the check before merge?

[ngarakapati]

1. Yes, Cloud Classic is included on purpose. .theme-cloud is the shared Savanna + Classic theme
2. This CI fail is because of existing infrastructure issue, not this PR.

@Tushar-TG-14