feat(mc-climate): add seismic, impact, tsunami event categories

Implements the three geological event categories end-to-end in
src/simulator/crates/mc-climate/src/events.rs, following the exact
same pattern as wildfire/drought/volcanic:

seismic:
  apply_seismic  — shifts tile.elevation by elevation_delta × distance
                   falloff over radius disk (clamped [0,1])
  dispatch_seismic — reads radius + elevation_delta from tiers JSON,
                     picks non-water center

impact:
  apply_impact   — two paths: T5 extinction (crater disk → desert,
                   global sulfate_aerosol injection, biome collapse
                   jungle→grassland/swamp→desert, site→mana_node) and
                   T1-T4 standard (crater terrain, elevation delta,
                   heat pulse via magic_heat_delta, local aerosol)
  dispatch_impact — reads elevation_delta/crater_radius/heat_*/aerosol_*
                    from tiers JSON; T5 uses aerosol_global path

tsunami:
  apply_tsunami  — floods non-water tiles in disk: moisture += moisture_gain,
                   quality = quality_reset (if >0); water tiles with
                   reef_destruction lose 0.5 reef_health
  dispatch_tsunami — picks IsCoast tile (returns None if no coast exists,
                     matching GDScript early-return); reads inland_reach/
                     moisture_gain/quality_reset/reef_destruction from tiers JSON

process_events match arms added for seismic, impact, tsunami.
pub mod events declared in lib.rs (was missing).
16 events tests total; all pass (cargo test -p mc-climate).

Config key notes:
  seismic JSON: elevation_delta (matches GDScript .get('elevation_delta'))
  impact JSON T5: uses crater_radius + elevation_loss (NOT elevation_delta)
  impact JSON T1-4: uses elevation_delta (may be negative for crater depression)
  tsunami JSON: inland_reach (not radius; radius in JSON is for T6+ global variants)
  scatter_resource/wonder_anchor bits: Game-3 deferred (same as volcanic)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/simulator/crates/mc-climate/src/lib.rs

@@ -1,4 +1,5 @@
 pub mod anomalous;
+pub mod events;
 pub mod atmosphere;
 pub mod climate_effects;
 pub mod derive;