Implement LLMville shared-world harvest and prepare 0.18.1

[Noisemaker111]

Shared topology left presence, commands and persistence unbounded, forcing LLMville to rebuild host behavior. This adds the missing engine contracts and migrates their consumer in https://github.com/Noisemaker111/ai-lab-game/pull/148.

• Core: scoped commands, decimal currency, elapsed accrual, quantity/rate/chat validation, territory placement and profile initialization.
• Convex: indexed neighborhood presence, shared membership/capacity, dirty-only writes, online batches, diagnostics/chat retention and territory storage.
• React/shell/transports: typed join failures with retry, chat focus behavior, placement cost feedback and pagehide leave.
• CLI/skills: shared-world-builder composition, capacity/economy/onboarding rules and generated API references.
• Prepare SDK 0.18.1, CLI 0.15.1 and GitHub adapter 0.5.1; include Rapier in lockstep publishing.

Verification: clean-checkout bun run build, bun run check-types (23 workspaces), bun run gen, and bun run ship:preflight pass. Focused primitive, host, scaffold and consumer tests pass. Source bun test packages: 7,212 pass, 1 skip, 1 fail (existing foot-IK failure); broader gate also reports baseline tooling/fixture failures. No release has been published.

Draft until the release test blocker is resolved. Automatic approval review rejected the unrelated foot-IK source/test fix as outside this report; explicit user approval is pending. No issues filed and no merge enabled.

LLMville HUD preview captures were inspected; Enter/Escape chat behavior and typing suspension were exercised. These prove component styling and feedback, not a deployed crowd-load benchmark.