[AIAA] Build step 5: data-collection scripts

Build step 5 (spec section 16, PR #363): the deterministic inventory
scripts behind HC-5, in `scripts/assessment/`.

Done when:

- [ ] The committed command, run twice against a sample project, yields
identical committed outputs (HC-5).
- [ ] A delegated session's draft PR contains the outputs its setup
steps produced (live check, recorded here).

Scope: collection CLI (file inventory, markdown link extraction, dated
site fetch), content-hash manifest with a verify mode (P-4, feeds the
section 15 Data field), agent-configuration snapshot script
(section 13), unit and determinism tests with `node:test`.

Parameterized around two section 17 build-time checks, answers recorded
here when a delegated exercise runs: how the target project reaches the
setup steps that run collection, and what the cloud-agent configuration
endpoint returns plus the credential it needs.