Update AGENTS.md with pre-submission check instruction

[google-labs-jules]

Added a new section "Pre-submission Checks" to AGENTS.md instructing developers/agents to run ./githooks/pre-push before submission.

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PR created automatically by Jules for task 5459663000946260746 started by @joshlf

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[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.14%. Comparing base (8f443eb) to head (b36144d).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2792   +/-   ##
=======================================
  Coverage   88.14%   88.14%           
=======================================
  Files          20       20           
  Lines        5450     5450           
=======================================
  Hits         4804     4804           
  Misses        646      646           

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[joshlf]

This is verbatim compiler output; please leave un-wrapped.

[google-labs-jules]

Reverted the wrapping of this compiler output line.