feat(simulation): planet_class temperature envelope, drop orbit/star inputs (T-1033, D-240)

Replace the sun-driven Stefan-Boltzmann temperature with the D-240 class-envelope
model. Temperature derives only from authored fields — no orbit/star physics.

- [planet_class_temperature] envelope table in climate_constants.toml (approved
  bands: frozen [-90,-25] .. hot_arid [20,58] .. volcanic [30,90]); cold_/hot_/
  warm_ prefix parsing; temperate fallback for unknowns.
- derive_temperature_c(params, constants, body_seed): band = envelope(planet_class);
  latitude lerps across it (equator=warm, pole=cold); atmosphere greenhouse +
  elevation lapse modulate within; small seed nudge for per-body variety; CLAMP to
  band — a body can never escape its class. Airless -> None.
- Delete the dead astrophysics: derive_distance_au, ClimateConstants::luminosity(),
  the [star_luminosity] table. Strip orbital_period_days/spectral_class/star_type/
  axial_tilt_deg from BodyParams + BodyParamsReader (read 3 cols from bodies, no
  star_systems join). DB columns left in place (no regen).
- New every_planet_class_derives_within_its_band test (13 classes x 5 atmo x 19 lat
  x 4 seeds, all in band) — the D-240 consistency guard.

Verified on 25 diverse real bodies: the worlds that derived to +356C now sit inside
their class bands (temperate capped at 28C). cargo test passes, clippy -D warnings
clean, fmt clean.

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

server/src/main.rs

@@ -215,10 +215,10 @@ fn main() {
         ),
     }
 
-    // Body physical params reader for RegionProfile carrier layer (T-1032, D-239 §1):
-    // reads hydrosphere / atmosphere / planet_class / orbital_period_days /
-    // axial_tilt_deg / spectral_class / star_type on a cache miss so the Rayon
+    // Body physical params reader for RegionProfile carrier layer (T-1032, D-239 §1, D-240):
+    // reads hydrosphere / atmosphere / planet_class on a cache miss so the Rayon
     // cascade work item stays DB-free (D-225 pattern).
+    // D-240: orbit/star fields are non-canonical and are no longer read.
     match settled_reach_server::atlas::body_params_reader::BodyParamsReader::open(&systems_db_path)
     {
         Ok(reader) => {