feat(server): initialize Rust/bevy_ecs simulation server

Server boilerplate epic (276) complete. Establishes the Rust simulation
server foundation per D-020 (subprocess/IPC architecture).

Structure:
- bevy_ecs 0.18 + bevy_app 0.18, MessagePack serialization (rmp-serde)
- SimulationPlugin with deterministic resources: SimulationTime (D-031),
  SimRng (D-030), InputQueue (D-010)
- Core IPC types: ObserverSnapshot, PlayerInput, SimBridge trait (D-020)
- CauseChain production component for provenance tracking (D-030)
- SimulationTier types with LRU eviction support (D-026)
- NPC 10-axis model components (D-024)
- 15 tests: inline unit tests + integration smoke/serialization tests
- make ci-server passes (clippy, fmt, build, test)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/main.rs

@@ -0,0 +1,31 @@
+// The Settled Reach - Simulation Server
+// Entry point for standalone simulation binary
+
+use bevy_app::prelude::*;
+use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt};
+
+use settled_reach_server::bridge::BridgePlugin;
+use settled_reach_server::simulation::SimulationPlugin;
+
+fn main() {
+    // Initialize tracing subscriber for logging
+    tracing_subscriber::registry()
+        .with(
+            tracing_subscriber::EnvFilter::try_from_default_env()
+                .unwrap_or_else(|_| "settled_reach_server=debug".into()),
+        )
+        .with(tracing_subscriber::fmt::layer())
+        .init();
+
+    tracing::info!("The Settled Reach - Simulation Server starting");
+
+    // Create the bevy App and add plugins
+    let mut app = App::new();
+    app.add_plugins(SimulationPlugin);
+    app.add_plugins(BridgePlugin);
+
+    // Run one update cycle
+    app.update();
+
+    tracing::info!("Simulation server update complete");
+}