Add whoami as a second real app (docs/08 hands-on exercise)

apps/whoami/deployment.yaml

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+# A tiny HTTP server that echoes back request details (headers, hostname,
+# IP) — useful as a second, real, end-to-end proof of the app-of-apps
+# pattern from docs/08-adding-new-apps.md: no storage, no privileged
+# access, just a Deployment and a Service like apps/demo/, but a completely
+# separate app added the normal way (drop files in apps/, commit, push).
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: whoami
+  namespace: whoami
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: whoami
+  template:
+    metadata:
+      labels:
+        app: whoami
+    spec:
+      containers:
+        - name: whoami
+          image: traefik/whoami:v1.10
+          ports:
+            - containerPort: 80

apps/whoami/namespace.yaml

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+# A Namespace is a way to group related resources together inside the
+# cluster, like a folder. Keeping "whoami" separate from other apps lets you
+# manage, view, and delete them independently (e.g. `kubectl -n whoami get pods`).
+#
+# We create this explicitly, as its own file, rather than letting Argo CD
+# invent it implicitly. That way it shows up in Git like everything else.
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: whoami

apps/whoami/service.yaml

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+# type: LoadBalancer asks MetalLB for a real, routable address from this
+# cluster's dedicated BGP service pool — see docs/05-metallb.md. 10.10.60.12
+# is the next free address in docs/network.md at the time this was added.
+apiVersion: v1
+kind: Service
+metadata:
+  name: whoami
+  namespace: whoami
+  annotations:
+    metallb.io/loadBalancerIPs: "10.10.60.12"
+spec:
+  type: LoadBalancer
+  selector:
+    app: whoami
+  ports:
+    - port: 80
+      targetPort: 80