M1 foundation: fix proxy, pool HTTP clients, split services, add ApiError + RLS

- Fix proxy body forwarding, round-robin load balancing, response streaming
- Pool reqwest::Client in proxy, control, and gateway (no per-request alloc)
- Harden CORS in gateway/main.rs (was allow_origin(Any), now uses ALLOWED_ORIGINS)
- Add common/src/error.rs: ApiError type with structured JSON responses
- Add common/src/rls.rs: RlsTransaction extractor for deduplicated RLS setup
- Fix tracing in all standalone binaries (EnvFilter instead of unused var)
- Dockerfile multi-stage: separate worker-runtime, control-runtime, proxy-runtime targets
- docker-compose.yml: split into worker/system/proxy services with health checks
- Fix Grafana port mapping in pillar-system (3030:3000)
- Add config/prometheus.yml and config/vmagent.yml
- Add .env.example with all required variables
- 55 tests pass (49 run + 6 ignored integration tests requiring external services)

Made-with: Cursor

functions/src/deno_runtime.rs

@@ -9,6 +9,11 @@ pub struct DenoRuntime {
     // In a production environment, we might want to pool runtimes or use isolates more efficiently
 }
 
+impl Default for DenoRuntime {
+    fn default() -> Self {
+        Self::new()
+    }
+}
 impl DenoRuntime {
     pub fn new() -> Self {
         Self {}