Add OSS Scanner build environment and threat model

[korridor]

Adds the files needed to enroll solidtime in Anthropic's OSS Scanner. The scanner builds .oss-scanner/Dockerfile with network access, then audits the image offline.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.62%. Comparing base (c994345) to head (5ab7a86).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #1310   +/-   ##
=========================================
  Coverage     93.61%   93.62%           
  Complexity     2327     2327           
=========================================
  Files           321      321           
  Lines         10971    10971           
=========================================
+ Hits          10271    10272    +1     
+ Misses          700      699    -1     

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[Onatcer]

@korridor do you think it is worth actually running octane/frankenphp as well as the scheduler/queue in this Docker image as well or no? it would be mainly for the request-state leaks and the sync driver. if not maybe we could just add it to the threat model as this is the actual state of the docker images that we publish.