feat(atlas): add gravity, orbital period, rotation + sync-wiki command

Schema: added orbital_period_days and rotation_period_hours to bodies
table. Proposal format now includes surface_gravity, orbital_period_days,
rotation_period_hours with sensible defaults per body type.

New sync-wiki command generates a Celestial Bodies section in wiki
pages from DB data. All 16 fields rendered including Year (d) and
Day (h). Re-authored Gateway (GJ 71) with full physics.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/data/systems-schema.sql

@@ -142,6 +142,8 @@ CREATE TABLE IF NOT EXISTS bodies (
     mass_class TEXT,                    -- terrestrial, super_earth, ice_giant, gas_giant, dwarf
     atmosphere TEXT,                    -- breathable, thin, toxic, none, dense
     surface_gravity REAL,              -- in g (Earth = 1.0), NULL for gas giants
+    orbital_period_days REAL,          -- orbital period in Earth days, NULL for oort/belt
+    rotation_period_hours REAL,        -- rotation period in Earth hours (Earth = 24), NULL for tidally locked/gas giants
     biome_summary TEXT,                -- temperate, arid, frozen, oceanic, volcanic, barren, mixed
     hydrosphere TEXT,                  -- ocean, ice, rivers, none, subsurface