Phayriosis Reborn Continued 0.1.1 - meteor stability maintenance

Baseline: 0.1.0 (stable universal-infection branch; no infected-container experiment code).

Changes:
- Meteor scheduler first eligible check delayed to 1200 ticks after world/server startup.
- Event meteor impact Y is snapped to the entity's actual landing Y before impact construction.
  This prevents stale launch-time height values from placing the buried meteor below the world.
- Meteor chunk tickets reduced: 7x7 impact-area ticket footprint and exact sampled flight-path chunks,
  removing the old 3x3 padding around every path sample.
- Surface infection and magma impact passes skip unloaded chunks instead of synchronously requesting them.
- Structurify 2.0.25 was inspected. The event meteor is manually block-built and is not a StructureStart,
  so Structurify overlap prevention does not participate in the event meteor and is intentionally not patched.

Continuation notes:
- Keep the event meteor independent of structure-overlap systems.
- Do not reintroduce large padded ticking-chunk corridors.
- Preserve the stable 0.1.0 universal-infection baseline when making future changes.
