feat(#52): era templates + shared scenario types/transforms
- presets/templates/: 3 light era templates (ww2/present/near-future) + index.json
manifest (id, name, year, eraDescription, suggestedPowers, tensions).
- server/templates.ts: createTemplateStore (mirror of createPresetStore).
- shared/scenario.ts: dependency-free contract for the dynamic scenario path —
SuggestedPower / EraTemplate / TemplateMeta / WorldNation / ScenarioEvent /
WorldDraft / Checkpoint types, relationFromScore, validateWorldDraft (pure,
defensive, never throws), worldDraftToGameState (region-key territory via the
injected expand resolver, regionStats seeded, clean turn-1 state).
- tests: server/templates.test.ts (manifest order + file shape),
server/scenario-shared.test.ts (15 cases: validation/clamp/dedup/null +
transform).
Fixes #52
kamilkrzywda
2191514db1