Initial commit: Rampart v0.2.0

Multi-layer DDoS protection for Minecraft servers.

- rampart-core: Edge node with XDP/eBPF + Rust L7 filtering
- rampart-manager: REST API with JWT auth, Redis sync
- rampart-cli: CLI tool for operators
- velocity-plugin: Domain check, HMAC verify, server registry, load balancer
- paper-plugin: Auto-registration, heartbeat, HMAC verify
- dashboard: React + Vite web UI for management

crates/rampart-manager/src/api/health.rs

@@ -0,0 +1,18 @@
+use crate::AppState;
+use axum::Json;
+use axum::extract::State;
+use serde::Serialize;
+use std::sync::Arc;
+
+#[derive(Serialize)]
+pub struct HealthResponse {
+    pub status: String,
+    pub version: String,
+}
+
+pub async fn health_check(State(_state): State<Arc<AppState>>) -> Json<HealthResponse> {
+    Json(HealthResponse {
+        status: "healthy".to_string(),
+        version: env!("CARGO_PKG_VERSION").to_string(),
+    })
+}