feat(simulation): dispatch RegionProfile layer in production (T-1032)

The D-239 carrier layer (T-1023/1024/1026) only ran in tests because every
production AnalyzeBody enqueue passed body_params: None. Wire the real path:

- New BodyParamsReader (server/src/atlas/body_params_reader.rs): read-only
  systems.db reader, joins bodies -> star_systems (LEFT JOIN) for the climate/
  tectonic inputs. SQL verified against systems-schema.sql. All fields Option,
  NULLs handled; tectonic_activity absent from schema -> None (derives from
  planet_class). 5 unit tests.
- layer_proxy.rs: on cache miss, read the body's params and pass
  Some(Box::new(..)). On read error, warn + fall back to None (cascade stops at
  Settlement, no panic) — graceful degradation.
- plugin.rs / main.rs: register BodyParamsReaderResource (CityContextReader
  pattern) and thread it through serve_atlas_requests.

BodyWorldState.regions now populates for real bodies in the D-206 background
pass. End-to-end tests cover wired (regions populated) + unwired (empty) paths.

cargo test 1504 pass, clippy -D warnings clean, fmt clean.

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

server/src/atlas/mod.rs

@@ -5,6 +5,7 @@
 
 pub mod attractor_matching;
 pub mod block_irregularity;
+pub mod body_params_reader;
 pub mod body_world_state;
 pub mod cascade;
 pub mod city_context_reader;