S129 — Every game plays the content it names

[The-Running-Dev]

What

A host can now keep more than one published version of a campaign available at once. Every game plays the version it names, not whichever version the host registered under the campaign's name. EngineHost.archive?: ResolutionArchive is optional. Without it, the engine uses an archive holding only the construction-time registry. Engine.content exposes whichever archive is in use.

• Every state-taking operation takes KindContext.registry and .campaign from content.resolve(state.campaignId, state.campaignVersion).
• createGame(config, campaignVersion?) starts on a named epoch.
• deserialize and migrate refuse a state whose epoch does not resolve, with unknown_campaign. This closes the S125.5 gap.

Criteria

• S129.1 — met: engine.test.ts › S129.1 — the archive in use
  • the default archive holds only the registry;
  • content is the supplied archive, and withEmitter keeps it;
  • construction throws on an archive missing the registry's epoch, or answering it with another version.
• S129.2 — met: S129.2 — every state-taking operation reads its own epoch
  • one engine, two epochs differing in one node's text;
  • scene, view, availableActions, submitAction, previewAction, deserialize and migrate each read the state's own epoch.
• S129.3 — met: S129.3 — createGame starts on the default or a named epoch
  • default version, named version, and unknown_campaign for an unresolved version or id.
• S129.4 — met: S129.4 — deserialize and migrate refuse an epoch that does not resolve
  • unknown_campaign plus exactly one core.deserialize.rejected, for a known id at another version.
  • Verified by reverting: both cases fail against the pre-slice kernel.
• S129.5 — met: the full suite passes with no existing test, golden file or corpus fixture changed (2,220 tests).
• S129.6 — met: engine.test.ts imports ResolutionArchive from src/index.ts, and the typecheck proves the root export.

Differs from design

• createEngine copies the registry's campaign map once, so a later mutation does not change the default epoch. One existing store test mutates the registry under a live engine. Recorded in 90-decisions.md, 2026-10-09.
• An archive answer whose registry holds the campaign at a different version counts as unresolved. Recorded in 90-decisions.md, 2026-10-09.

Verified

• npm run typecheck, npm run lint: clean.
• npm test: 115 files, 2,220 tests passed.
• ./build/Test-Documentation.ps1: passed (drift check across 19 generated pages; 135 Markdown files).
• git diff --check: clean.
• Advisory test-design.ts reported 13 findings. All are path fragments such as /authoring read as slash commands. They predate this change, and none are in lines this PR touches.
• Not run locally: ./docs.ps1 -BuildOnly (no installed docs.ps1). The Verify Documentation Build check covers it.