feat: apply namespaces, wire make cluster-up end-to-end

[CodeBuildder]

What this does

Closes #5.

Wires make cluster-up into a single end-to-end command that takes a Mac from zero to a fully running Argus cluster. Also applies the four core namespaces (prod, staging, monitoring, argus-system) and fills in the README Local setup section.

Changes

Makefile

• cluster-up now runs all four bootstrap scripts in sequence and finishes with kubectl apply -f cluster/namespaces/namespaces.yaml — one command to go from bare metal to running cluster
• cluster-status improved with section headers (nodes, pods, Cilium status)
• deploy-falco and deploy-kyverno replaced with real Helm commands — stubs removed
• Dropped stale deploy-cilium target (handled by 04-install-cilium.sh inside cluster-up)
• .PHONY updated to match all targets

cluster/namespaces/namespaces.yaml

• Four namespaces with consistent app.kubernetes.io/managed-by: argus label: prod, staging, monitoring, argus-system

README.md

• Replaced [fill in after Module 1 is complete] placeholder with a real Local setup section: prerequisites, make cluster-up, and verify steps

Impact

Module 1 is now fully complete. Any contributor can clone the repo, run make cluster-up, and have a production-like 3-node k3s cluster with Cilium eBPF, Hubble, and all namespaces in a single command.