docs(defaults): correct MirrorDefaultKubeVersion rationale comment

The comment claimed the value "tracks the project's minimum supported
Kubernetes version declared in recipes/overlays/base.yaml". It does not,
and must not: base.yaml declares ">= 1.25" while the constant is 1.33.0.

The constant is a render-safe fallback for `helm template --kube-version`
used by pkg/helm/render.go and pkg/mirror/discover.go when no version is
supplied. Two sentences earlier the same comment explains why it exists —
Helm's compiled-in v1.27.0 default is too old for charts declaring
`kubeVersion: >=1.32.0-0`. Lowering the value to 1.25 to match base.yaml
would reintroduce exactly that failure.

The value is correct; only the rationale was wrong. Rewritten to state
that this is a fallback rather than a support floor, and to warn against
the plausible-looking "fix" of aligning it with base.yaml. Also notes
that a recipe declaring K8s.server.version never reaches this default
(mirror.KubeVersionFromConstraints returns the recipe's own value).

Comment-only; no behavior change.

Signed-off-by: Yuan Chen <yuanchen97@gmail.com>

Author: yuanchen8911

pkg/defaults/timeouts.go

@@ -1254,8 +1254,13 @@ const (
 	// recipe constraints. Without this flag Helm uses its compiled-in
 	// default (currently v1.27.0 in Helm 3.x), which is too old for
 	// charts that declare a kubeVersion constraint (e.g., >=1.32.0-0).
-	// The value tracks the project's minimum supported Kubernetes version
-	// declared in recipes/overlays/base.yaml.
+	//
+	// This is a render-safe fallback, not a support floor. It must stay at
+	// or above the strictest kubeVersion any bundled chart declares. Do NOT
+	// lower it to match the ">= 1.25" recipe floor in
+	// recipes/overlays/base.yaml: that is the constraint recipes are
+	// validated against, and a recipe that declares one never reaches this
+	// default (see mirror.KubeVersionFromConstraints).
 	MirrorDefaultKubeVersion = "1.33.0"
 
 	// MirrorDiscoveryConcurrency caps the number of components rendered in