fix(ado-script): flatten bundled artifacts to top-level gate.js/import.js

[Copilot]

Summary

This change removes the scripts/ado-script/dist/*/index.js runtime contract and switches the system to flat artifact names (gate.js, import.js) inside ado-script.zip. Compiler-emitted pipeline steps now execute those files directly by name.

• Build/output layout

  • Updated scripts/ado-script/package.json build scripts to emit flat gate.js / import.js artifacts (no dist/ output contract).
  • Updated ignore rules to match the new artifact/temp layout.

• Runtime wiring

  • Updated AdoScriptExtension runtime paths to:
    • /tmp/ado-aw-scripts/ado-script/gate.js
    • /tmp/ado-aw-scripts/ado-script/import.js
  • Updated release packaging to include flat files directly in ado-script.zip.

• Verification surface updates

  • Updated Rust tests, TS smoke tests, and compiler assertions that previously referenced dist/.../index.js.
  • Updated docs (repo docs + site docs) to reflect the flat artifact contract.

const GATE_EVAL_PATH: &str = "/tmp/ado-aw-scripts/ado-script/gate.js";
pub(crate) const IMPORT_EVAL_PATH: &str = "/tmp/ado-aw-scripts/ado-script/import.js";

Test plan

• cargo test
• cargo clippy --all-targets --all-features
• cd scripts/ado-script && npm run build && npm run typecheck && npm test && npm run test:smoke