feat(simulation): hydrosphere maritime moderation of temperature (T-1033, D-240)

Add the D-240 hydrosphere modulator: water-rich worlds compress the equator->pole
temperature gradient toward the band midpoint (milder at both ends); dry worlds
swing the full class band.

- [hydrosphere_maritime] table in climate_constants.toml + ClimateConstants
  field/method (maritime_factor). Keyed on the ACTUAL bodies.hydrosphere vocab
  (liquid_water/ocean/extensive=0.6, rivers/moderate=0.8, ice=0.85, subsurface*
  =0.9-0.95; minimal/trace/none/NULL -> 1.0).
- derive_temperature_c step 2 now lerps across a maritime-compressed sub-band
  (mid +/- band_half*factor) instead of the full band. Clamp still guarantees the
  class-band invariant.
- New maritime_hydrosphere_compresses_the_gradient test (ocean delta < dry delta).

Verified on real worlds: liquid_water/ocean temperate worlds now delta ~24 (milder)
vs dry ~40, all in-band. cargo test passes, clippy -D warnings clean, fmt clean.

Note: discovered derive_moisture_q has the SAME vocab mismatch (expects 'ocean',
DB uses 'liquid_water' for 175 bodies -> falls to default moisture). Pre-existing,
out of scope here — filing a follow-up.

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

server/data/climate_constants.toml

@@ -65,3 +65,22 @@ standard   = 15   # ~15°C: Earth-like moderate swing
 toxic      = 20   # intermediate: thick but maybe less redistribution
 breathable = 15   # synonym for standard
 dense      = 3    # ~3°C: Venus-like near-uniform temperature
+
+# ---------------------------------------------------------------------------
+[hydrosphere_maritime]
+# Maritime moderation (D-240): scales the equator→pole temperature gradient by
+# hydrosphere. 1.0 = full gradient (dry world swings the whole class band);
+# < 1.0 compresses toward the band midpoint (water-rich worlds are milder at
+# both poles and equator). Keys = actual bodies.hydrosphere vocabulary in
+# systems.db. "minimal"/"trace"/"none"/absent default to 1.0 in code.
+liquid_water      = 0.6   # large surface liquid — strongly moderated
+ocean             = 0.6
+"ocean-coastal"   = 0.6
+extensive         = 0.6
+rivers            = 0.8   # partial surface water — mild moderation
+"rivers-lakes"    = 0.8
+moderate          = 0.8
+ice               = 0.85  # frozen surface — slight moderation
+subsurface_liquid = 0.9
+subsurface        = 0.95  # buried water — minimal surface effect
+subsurface_ice    = 0.95