fix: fully restore the terminal when ClearScreen is used

[andrinoff]

Something outside the renderer (a child process or another writer) can reset terminal modes, e.g. by emitting ESC[?1049l. The renderer still believes its alt-screen frame and modes are in place, so a redraw lands on the primary screen and mouse tracking, bracketed paste, focus reporting, keyboard enhancements, and cursor style stay lost.

[codecov]

Codecov Report

❌ Patch coverage is 58.62069% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.88%. Comparing base (33f6a40) to head (b964df6).

Files with missing lines	Patch %	Lines
cursed_renderer.go	58.62%	7 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1837      +/-   ##
==========================================
+ Coverage   59.91%   60.88%   +0.97%     
==========================================
  Files          25       25              
  Lines        1342     1350       +8     
==========================================
+ Hits          804      822      +18     
+ Misses        449      443       -6     
+ Partials       89       85       -4     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.