Phase 7A - Create World meteor settings foundation (0.0.18)

Known-good base: 0.0.17.10 Phase 6 brighter-flash/water-safe build. Phase 6 meteor flight, chunk loading,
impact, sound, shockwave, flash, terrain, defenders, ores and 500 HP Nucleus are intentionally frozen.

This phase adds a new client-only Create World entry point without reviving the old MCreator ConfigScreen.
- Forge ScreenEvent.Init.Post adds a "Phayriosis Settings" button to vanilla CreateWorldScreen.
- New PhayriosisWorldCreationScreen is a functional, deliberately plain foundation UI; pixel-art styling/tabs come later.
- Current functional controls: meteor enabled, earliest day, minimum phase, chance, check interval,
  impact-distance preset, and impact infection enabled.
- Pending values are ephemeral client/JVM state until the new integrated world actually starts.
- On first login of a genuinely fresh world, PhayriosisWorldSettings.ensureInitialized calls
  PhayriosisPendingWorldSettings.consumeInto before legacy mirroring. It sets worldCreationConfigured=true,
  persists to SavedData, then clears the pending profile.
- Existing worlds are protected: consume requires uninitialized/unconfigured Phayriosis settings and early game time.
- Navigating back to Select World or Title clears the pending draft so cancelled world creation does not leak settings.
- Dedicated servers never load/register the client screen hook; without a pending client profile the existing backend behaves unchanged.

Do not remove the old internal ConfigScreen/Menu classes yet; they remain inert compatibility baggage from Phase 1.
Do not reuse them for the new world-creation UI.
