docs: update status with MeshNode integration

docs/status.md

@@ -58,6 +58,47 @@
 
 ---
 
+## 2026-04-01 — MeshNode: Production Integration
+
+### Completed
+- **MeshNode** — `mesh_node.rs`: Production-ready node integrating all subsystems
+  - `MeshNodeBuilder`: Fluent API for configuration
+  - `MeshConfig` integration for all settings
+  - `MeshMetrics` tracking for all operations
+  - Rate limiting on incoming messages via `RateLimiter`
+  - Backpressure control via `BackpressureController`
+  - Graceful shutdown via `ShutdownCoordinator`
+  - Optional `FappRouter` based on capabilities
+  - `MeshRouter` for envelope routing
+  - `TransportManager` for multi-transport support
+
+### Key APIs
+```rust
+// Build a mesh node
+let node = MeshNodeBuilder::new()
+    .config(config)
+    .identity(identity)
+    .fapp_relay()
+    .fapp_patient()
+    .build()
+    .await?;
+
+// Process incoming with rate limiting + metrics
+let action = node.process_incoming(&sender_addr, envelope)?;
+
+// Garbage collection
+node.gc()?;
+
+// Graceful shutdown
+node.shutdown().await;
+```
+
+### Test Coverage
+- 222 total tests (203 lib + 3 fapp_flow + 16 multi_node)
+- 5 new mesh_node tests
+
+---
+
 ## 2026-04-01 — FAPP: Complete E2E Flow
 
 ### Completed (Latest)