feat(ai): send number of secrets detected by ai agent hook

[pbeslin-gg]

Context

What has been done

Validation

Depends on GitGuardian/py-gitguardian#185
When an AI agent hook blocks a secret, an event is sent to the GitGuardian API with metadata on the hook execution (including the number of secrets detected, but not their values).

PR check list

• As much as possible, the changes include tests (unit and/or functional)
• If the changes affect the end user (new feature, behavior change, bug fix) then the PR has a changelog entry (see doc/dev/getting-started.md). If the changes do not affect the end user, then the skip-changelog label has been added to the PR.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.66%. Comparing base (a7b9216) to head (c0a72b0).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1313   +/-   ##
=======================================
  Coverage   93.65%   93.66%           
=======================================
  Files         189      190    +1     
  Lines       11088    11105   +17     
=======================================
+ Hits        10385    10402   +17     
  Misses        703      703           

Flag	Coverage Δ
unittests	93.66% <100.00%> (+<0.01%)	⬆️

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