Prepare Drawing 3.1.3 with updated licensing and dependencies

[JimBobSquarePants]

Prerequisites

• I have written a descriptive pull-request title
• I have verified that there are no overlapping pull-requests open
• I have verified that I am following matches the existing coding patterns and practice as demonstrated in the repository. These follow strict Stylecop rules 👮.
• I have provided test coverage for my change (where applicable)

Description

Prepare Drawing 3.1.3 on release/3.1.x.

• Update SharedInfrastructure from release/4.1.x to include Licensing 1.0.3, repository guidance, and the security policy.
• Update dependencies to ImageSharp 4.1.3 and Fonts 3.2.0.

• Update PolygonClipper to 1.0.2 so all dependencies use Licensing 1.0.3.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80%. Comparing base (17815ec) to head (e66982c).

Additional details and impacted files

@@              Coverage Diff              @@
##           release/3.1.x    #426   +/-   ##
=============================================
- Coverage             80%     80%   -1%     
=============================================
  Files                232     232           
  Lines              27413   27413           
  Branches            3126    3126           
=============================================
- Hits               21946   21945    -1     
  Misses              4578    4578           
- Partials             889     890    +1     

Flag	Coverage Δ
unittests	80% <ø> (-1%)	⬇️

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