Cleanup build caches

Workflow runs for Cleanup build caches

• Add .github/copilot-instructions.md for cloud agent onboarding

  completed successfully:
  Cleanup build caches#9:Pull request#9closedbyhansec
  copilot/add-copilot-instructions

  Apr 22, 202614s
  More actions for workflow run 9

• CI: Fix prune_cache workflow to correctly delete PR-scoped caches on close

  completed successfully:
  Cleanup build caches#8:Pull request#10closedbyhansec
  copilot/update-prune-cache-workflow

  Apr 19, 202612s
  More actions for workflow run 8

• Fix copilot-setup-steps: export CC/CXX/FC via GITHUB_ENV to work around Copilot job-env restriction

  completed successfully:
  Cleanup build caches#7:Pull request#11closedbyhansec
  copilot/fix-copilot-setup-check-compilers

  Apr 19, 202614s
  More actions for workflow run 7

• TokaMaker: Add normalization to non-uniform coils

  completed successfully:
  Cleanup build caches#6:Pull request#7closedbyhansec
  DeIonizedPlasma:tMaker_vcoils

  Mar 27, 202614s
  More actions for workflow run 6

• Base: Add C array parsing with 2D shape support to LIBXML2 Fortran interface

  completed successfully:
  Cleanup build caches#5:Pull request#6closedbyhansec
  copilot/add-libxml2-fortran-interface

  Mar 12, 202612s
  More actions for workflow run 5

• Add copilot-setup-steps.yml for GitHub Copilot agent environment setup

  completed successfully:
  Cleanup build caches#4:Pull request#5closedbyhansec
  copilot/add-copilot-setup-steps

  Mar 5, 202613s
  More actions for workflow run 4

• Eddy plotting

  completed successfully:
  Cleanup build caches#2:Pull request#3closedbyhansec
  DeIonizedPlasma:tMaker_vcoils

  Dec 21, 202511s
  More actions for workflow run 2