Deterministic include manifest ordering while preserving import topology

[davidahmann]

Problem observed

Workflow lock/header output can drift when include lists are emitted in non-canonical order. Even when behavior is unchanged, this produces noisy diffs and weakens trust in lock artifacts as deterministic receipts for maintainers and automation.

Why it matters operationally

Non-semantic drift increases review load and can hide real behavior changes. In a fast-moving repo, this also creates avoidable CI churn and makes it harder to reason about what changed between two compiles on different environments.

Minimal repro

gh aw compile .github/workflows/sample.md
# reorder include declarations in source
gh aw compile .github/workflows/sample.md
# compare lock/header manifest output

Fix approach

The change canonicalizes IncludedFiles rendering in header generation while preserving import dependency ordering. ImportedFiles remain topological, so dependency semantics stay intact and no runtime contract changes are introduced.

Validation evidence

• Added/updated header helper tests for deterministic include ordering.
• Verified import topology test still passes.
• Confirmed scoped workflow package tests pass on the patch.

Open follow-up question for maintainers

Would you prefer a follow-up that emits an explicit “manifest ordering contract” note in docs so downstream tooling can rely on the include ordering guarantee?

This contribution was informed by patterns from Gait: https://github.com/davidahmann/gait