Add terminal maximize focus view

[kunal-9090]

Closes #162

GSSoC

• Label: gssoc:approved
• Level: level:advanced

Summary

• Adds a terminal maximize/focus toggle in the terminal utility bar.
• Tracks maximized state in the existing UI state object.
• Toggles a terminal-maximized layout class to hide the sidebar, analysis panel, and resizers while expanding the terminal area.
• Keeps button title, aria label, and pressed state synchronized.
• Allows Escape to restore the normal terminal layout.

Validation

• node --check ui/app.js
• rg -n btn-maximize-terminal|terminalIsMaximized|terminal-maximized|toggleTerminalMaximized|setTerminalMaximized ui/index.html ui/app.js ui/style.css
• git diff --check

[kunal-9090]

Hi @siddu-k, I fixed the Python security check blocker and pushed the follow-up commit. This PR is now mergeable and both CI jobs are green.