🤖 docs: create coder namespace in contributing quick start

Add an explicit `kubectl create namespace coder` step before applying the sample control plane so the CONTRIBUTING quick-start works with namespaced sample manifests.

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Author: ThomasK33

CONTRIBUTING.md

@@ -21,7 +21,8 @@ kubectl apply -f config/crd/bases/
 # Run controller locally against your kubeconfig context
 GOFLAGS=-mod=vendor go run . --app=controller
 
-# In another terminal, apply a sample control plane
+# In another terminal, create the sample namespace and apply a sample control plane
+kubectl create namespace coder
 kubectl apply -f config/samples/coder_v1alpha1_codercontrolplane.yaml
 
 # Verify resource creation