feat: add metrics, observability, test fixtures, and scaling playbook artifacts

scripts/loadtest/ws-chat.yml

@@ -0,0 +1,28 @@
+config:
+  target: "{{ $processEnvironment.WS_URL }}"
+  phases:
+    - duration: 60
+      arrivalRate: 10
+      name: warmup-10
+    - duration: 120
+      arrivalRate: 100
+      name: sustain-100
+    - duration: 180
+      arrivalRate: 500
+      name: sustain-500
+    - duration: 240
+      arrivalRate: 1000
+      name: sustain-1000
+  engines:
+    ws: {}
+scenarios:
+  - engine: ws
+    name: chat-presence-and-send
+    flow:
+      - think: 1
+      - send:
+          text: '{"type":"ping","text":"loadtest"}'
+      - think: 1
+      - send:
+          text: '{"type":"ping","text":"loadtest-2"}'
+      - think: 1