Each per-feature LLM ability is now a self-contained module in
server/abilities/ with its own Ability<K> const (schema line, constraint
bullet, validator, applier, isMeaningful, stub default, user-payload
field). The ordered ABILITIES registry (index.ts) assembles them in the
canonical order: takeovers → wars → hybrid → economy → industry → nuclear
→ leaders → ideology.
All function bodies are moved VERBATIM from engine.ts. The engine is
untouched in this commit — P4 will rewire it to use the registry.
Move the 5 shared reference/id primitives (resolveNationRef, resolveRegionKey,
freshNationId, freshWarId, NEW_NATION_STATS) from engine.ts into the new
server/abilities/shared.ts (breaking the engine<->ability import cycle), and
add server/abilities/types.ts with the Ability<K> interface + AbilityCtx /
UserPromptCtx types that the 8 per-feature ability modules will implement.
engine.ts imports the helpers and re-exports them so existing callers
(server/index.ts, the unit tests) are untouched. Behavior is identical; all
511 unit tests, lint and typecheck stay green.
kamilkrzywda