Remove redundant per-repo workflows in favor of centralized CI

[tillig]

Removes the per-repo workflow files (build.yml, ci.yml, dotnet-format.yml, pre-commit.yml, publish.yml) now that CI is driven by the centralized reusable workflow in autofac/.github via main.yml.

The old files and main.yml currently both run; this removes the redundant duplicates so only the shared workflow remains.

Part of the org-wide CI centralization.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 77.65%. Comparing base (5ba7e16) to head (7405e46).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1483      +/-   ##
===========================================
- Coverage    77.69%   77.65%   -0.04%     
===========================================
  Files          217      217              
  Lines         5827     5827              
  Branches      1252     1252              
===========================================
- Hits          4527     4525       -2     
- Misses         764      765       +1     
- Partials       536      537       +1     

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