fix(examples): move pony examples, fix broken build

[caarlos0]

• move pony examples into the right folder
• one go.mod for all of them so ./scripts/build doesn't go crazy

[codecov]

Codecov Report

❌ Patch coverage is 0% with 14 lines in your changes missing coverage. Please review.
✅ Project coverage is 39.96%. Comparing base (9f73bfd) to head (4fceb84).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
examples/cellbuf/main.go	0.00%	3 Missing ⚠️
examples/pony/interactive-form/main.go	0.00%	3 Missing ⚠️
examples/layout/main.go	0.00%	2 Missing ⚠️
examples/pony/scrolling-markup/main.go	0.00%	2 Missing ⚠️
examples/pony/buttons/main.go	0.00%	1 Missing ⚠️
examples/pony/scrolling-with-clicks/main.go	0.00%	1 Missing ⚠️
examples/pony/scrolling/main.go	0.00%	1 Missing ⚠️
examples/pony/stateful/main.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #690      +/-   ##
==========================================
+ Coverage   36.95%   39.96%   +3.01%     
==========================================
  Files         188       50     -138     
  Lines       16695     3816   -12879     
==========================================
- Hits         6169     1525    -4644     
+ Misses      10145     2199    -7946     
+ Partials      381       92     -289     

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