feat: add SARIF result format

[twelvelabs]

• Adds ability to render stylist results as a SARIF report.
• Updates SARIF dependency to v2.
• Fixes JSON printer to respect the ShowContext config setting/flag.

Closes #5

[codecov]

Codecov Report

Attention: 3 lines in your changes are missing coverage. Please review.

Comparison is base (8581bb2) 91.24% compared to head (82e6f67) 91.36%.

Files	Patch %	Lines
internal/stylist/result_printer.go	94.91%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #98      +/-   ##
==========================================
+ Coverage   91.24%   91.36%   +0.11%     
==========================================
  Files          18       18              
  Lines        1668     1725      +57     
==========================================
+ Hits         1522     1576      +54     
- Misses        105      107       +2     
- Partials       41       42       +1     

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