feat(packages): move the Reference Packages to the collection

[Mathih13]

Core ships an inert Reference Package and a disabled Fire Nova example. Authors now have five working Reference Packages in the Official Package Collection, selected by the checkout's Package API version.

Remove both in-tree examples and their special build rule. Keep Fire Nova as a synthetic Datascript test fixture. Core's Package ownership, teardown and Runtime Script tests use their own name; the disposable test Module enables an inert Package fixture through a test-only feature. Normal builds do not register it. Update the glossary and authoring docs, and pin the CLI that builds Package-local Datascripts and scaffolds from the collection.

Closes #636.

The preceding changes are merged: Packages #77 and #78, and CLI #66, #68 and #69. The issue owner confirmed that example-data keeps its Datascript as source and builds the Delta locally. No Package Delta is committed to the collection.

What you verified

• All 45 Datascript and Runtime Script tests pass, including the moved Fire Nova fixture and its regenerated synthetic expected artifact. The obsolete test for checked-in Package scripts was removed after CI identified it.
• The collection passed 1,870 Module library tests, a synthetic Datascript build, artifact checks and CI. Its complete diff cleared independent Standards and adversarial Spec reviews.
• The CLI passed 760 tests, Clippy and its MSRV check. Its final diff cleared both independent reviews. The actual CLI fetched, renamed, preflighted and built all five rungs from api-v1 against a synthetic Base Snapshot. Provenance, artifact names, Build Identity sidecars and addon paths passed checks.
• Core passed 1,757 Module library tests, 10 Datascript interoperability tests and all 9 tests across the three durable Package suites. The pinned CLI installs, exposes help, and refuses an unknown scaffold rung without creating a Package. All 45 Datascript and Runtime Script tests pass.

What you did not verify

No production access or real-client session. The client example's addon and UI Transform insertion were checked with Lua; this does not prove actual display in the client.

Risk

Build discovery, test fixtures, the CLI pin and Package authoring docs. No schema or protocol changes. The separate package_test_fixture feature is used by the disposable test Module and is absent from the normal publish command.

Notes for the reviewer

Independent Standards and adversarial Spec subagents cleared final commit 6a531071 after fixes to stale Datascript and Official Package update documentation. The issue owner requested these reviews in place of the automatic review trigger. CLI #70 applies the same documentation corrections to the CLI guide.

Implemented with GPT-6 Astra in the Codex harness through T3 Code.