Remove STI and MTI implementations

[alganet]

These features reached blocker limitations for future designs and will be re-planned from scratch later.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.96%. Comparing base (c7ab409) to head (da50849).

Additional details and impacted files

@@             Coverage Diff              @@
##             master      #30      +/-   ##
============================================
+ Coverage     98.07%   98.96%   +0.88%     
+ Complexity      253      237      -16     
============================================
  Files            15       13       -2     
  Lines           520      481      -39     
============================================
- Hits            510      476      -34     
+ Misses           10        5       -5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.