feat(analytics): Implement semver and date custom ops for flags runtime props

[efahk]

Adds Semantic Versioning and RFC3339 date comparison support for feature flags runtime event matching. This implements them as extensions to the JSONLogic library that is being used for targeting.

See here for more information about the comparators and golden vector list

[greptile-apps]

Confidence Score: 3/5

The PR is not yet safe to merge because datetime precision and SemVer prerelease case handling can still select incorrect flag variants.

Datetime operands are still reduced to whole seconds, and runtime rule preprocessing still case-folds SemVer strings before case-sensitive prerelease comparison.

Files Needing Attention: mixpanel/flags/custom_operators.py, mixpanel/flags/local_feature_flags.py

Important Files Changed

Filename	Overview
mixpanel/flags/custom_operators.py	Implements validation, normalization, and comparison logic for the two new JSONLogic operators.
mixpanel/flags/local_feature_flags.py	Registers the operators in the local feature-flag evaluation path.
mixpanel/flags/test_custom_operators.py	Exercises operator registration, golden vectors, malformed operands, and invalid dates.
pyproject.toml	Includes custom-operator golden-vector JSON files in package data.

_{Reviews (10): Last reviewed commit: "simplify date check" | Re-trigger Greptile}

[codecov]

Codecov Report

❌ Patch coverage is 97.29730% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.33%. Comparing base (176d855) to head (b66a8ac).

Files with missing lines	Patch %	Lines
mixpanel/flags/custom_operators.py	95.80%	3 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #193      +/-   ##
==========================================
+ Coverage   96.25%   96.33%   +0.08%     
==========================================
  Files          13       15       +2     
  Lines        2616     2838     +222     
  Branches      139      176      +37     
==========================================
+ Hits         2518     2734     +216     
- Misses         64       67       +3     
- Partials       34       37       +3     

Flag	Coverage Δ
openfeature-provider	50.71% <21.52%> (-3.35%)	⬇️

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[tylerjroach]

@greptileai re-review