Compiled workflows were embedding the full builtin model alias map into awf-config.json, inflating lock output and coupling runtime behavior to heavyweight serialized config. This change stores only workflow/import alias deltas and reconstructs the effective mapping at runtime by merging against the bundled base alias file.

• Compiler output: serialize delta, not full map

  • Added BuildModelAliasesDelta(...) in pkg/workflow/model_aliases.go.
  • BuildAWFConfigJSON now writes apiProxy.models only when aliases differ from builtins (new keys or overrides).
  • Builtin-only workflows omit apiProxy.models entirely.

• Runtime reconstruction in setup action

  • Added actions/setup/js/merge_model_aliases.cjs.
  • At runtime, it reads:
    • base aliases: .../actions/model_aliases.json
    • workflow delta: awf-config.json -> apiProxy.models
  • It rewrites awf-config.json with the merged alias map used by AWF.

• Setup wiring and bundled data

  • Bundled actions/setup/js/model_aliases.json into setup assets.
  • Updated AWF command setup (pkg/workflow/awf_helpers.go) to invoke merge helper before AWF starts.
  • Introduced explicit path constants for config and bundled alias file to keep runtime wiring centralized.

• Behavioral contract updates

  • Updated Go tests to assert delta-only emission semantics.
  • Added JS tests for merge helper behavior (override, additive alias, no-op when delta absent).
  • Updated wasm golden outputs for the new setup command sequence.

# New runtime step inserted before AWF invocation
node "${RUNNER_TEMP}/gh-aw/actions/merge_model_aliases.cjs" \
  "${RUNNER_TEMP}/gh-aw/awf-config.json" \
  "${RUNNER_TEMP}/gh-aw/actions/model_aliases.json"