Remove moderation workflow

[martincostello]

Remove workflow added in #2725 as it won't work without the Models tab enabled (HTTP 403 errors).

[Copilot]

Pull Request Overview

This PR removes the GitHub Actions moderation workflow that was previously added to detect spam and AI-generated content. The workflow is being removed because it requires the Models tab to be enabled in the repository, which is currently causing HTTP 403 errors when the workflow attempts to run.

• Removes the entire .github/workflows/moderation.yml file
• Eliminates the spam detection job and AI moderation functionality
• Prevents HTTP 403 errors that occur when the workflow tries to access models without proper permissions

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.12%. Comparing base (3ed1030) to head (7231d68).
⚠️ Report is 4 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2729   +/-   ##
=======================================
  Coverage   96.12%   96.12%           
=======================================
  Files         309      309           
  Lines        7118     7118           
  Branches     1008     1008           
=======================================
  Hits         6842     6842           
  Misses        222      222           
  Partials       54       54           

Flag	Coverage Δ
linux	96.12% <ø> (ø)
macos	96.12% <ø> (ø)
windows	96.11% <ø> (ø)

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