[Quim Muntal (qmuntal)]

Summary

• Remove all four explicit model pins from the agentic workflow sources, including GPT-5.5 and GPT-5.6, without pinning a replacement.
• Use repository defaults or automatic model selection instead of requiring an unavailable model.
• Regenerate the affected workflow locks and action-pin cache with the existing gh-aw v0.92.0 compiler; preserve workflow prompts and intent.

Fixes #1305.

Validation

• Strict compilation of all four affected workflows with gh-aw v0.92.0: passed with zero warnings.
• All five agentic workflows report current lock files.
• Verified no explicit model selections remain in workflow sources or generated model metadata.
• Verified workflow prompt hashes and compiler versions are unchanged.
• git diff --check and staged whitespace checks passed; no binaries were staged.

[Copilot]

🟢 Approval recommended

Source and generated changes consistently implement default model selection, with no blocking issues identified.

No open issues 🎉

What changed in this PR

Removes hardcoded model selections from the repository’s maintenance workflows to address the unavailable-model failure in #1305.

Changes:

• Remove four model pins, allowing repository defaults or automatic selection.
• Regenerate workflow locks while preserving prompts and compiler version.
• Record the setup action’s immutable commit pin.

File	Description
.github/​workflows/​symbolmap-maintenance-weekly.md	Remove model pin.
.github/​workflows/​symbolmap-maintenance-weekly.lock.yml	Regenerate model defaults and scattered schedule.
.github/​workflows/​dotnet-port-fixes-nightly.md	Remove model pin.
.github/​workflows/​dotnet-port-fixes-nightly.lock.yml	Regenerate model defaults and action references.
.github/​workflows/​dotnet-port-api-nightly.md	Remove model pin.
.github/​workflows/​dotnet-port-api-nightly.lock.yml	Regenerate model defaults and action references.
.github/​workflows/​dotnet-code-portability-weekly.md	Remove model pin.
.github/​workflows/​dotnet-code-portability-weekly.lock.yml	Regenerate model defaults and scattered schedule.
.github/​aw/​actions-lock.json	Cache the setup action’s commit pin.

_{Review effort: Balanced}