Initial commit: GitOps Starter Pack

A teaching-first, single-cluster GitOps setup: Talos Linux + Argo CD with
an app-of-apps layout, MetalLB pre-installed for real LoadBalancer IPs on
bare metal, a demo app, and a progressive docs/ walkthrough with a
CLAUDE.md tutor persona and guided bootstrap checklist.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/metallb/templates/l2advertisement.yaml

@@ -0,0 +1,19 @@
+# L2Advertisement is what actually makes addresses from the pool reachable:
+# it tells MetalLB to answer ARP requests for whichever address a Service
+# was given, from whichever node currently hosts that Service. This is
+# "Layer 2 mode" — the simplest of MetalLB's two modes, and the right
+# choice here since it needs no cooperation from your router (the
+# alternative, BGP mode, does — worth knowing exists if you outgrow a
+# single L2 segment, not needed for this setup).
+# Same sync-wave reasoning as ipaddresspool.yaml — deferred to wave "1" so
+# it applies after MetalLB's own chart resources are up.
+apiVersion: metallb.io/v1beta1
+kind: L2Advertisement
+metadata:
+  name: default
+  namespace: metallb-system
+  annotations:
+    argocd.argoproj.io/sync-wave: "1"
+spec:
+  ipAddressPools:
+    - default-pool