docs: update install docs to headlamp namespace (PRI-434)

- Update Helm/plugin install URLs from v0.2.4 to v1.0.0
- README: add pods/proxy RBAC scope, clarify controller is in kube-system
- docs/getting-started/*: update all download URLs to v1.0.0
- docs/deployment/helm.md: update install URLs to v1.0.0
- docs/architecture/overview.md: Headlamp Pod label → headlamp namespace
- docs/README.md: fix ArtifactHub URL
- CHANGELOG.md: add [Unreleased] entry

Note: driver/API-path references to kube-system are preserved
as they describe where the tns-csi controller workload runs,
not where Headlamp is installed.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

docs/architecture/overview.md

@@ -28,7 +28,7 @@ The TNS-CSI plugin is a single-page React application bundled as a Headlamp plug
                         │ HTTPS
                         ▼
 ┌─────────────────────────────────────────────────────┐
-│              Headlamp Pod (kube-system)              │
+│              Headlamp Pod (headlamp namespace)              │
 │                                                     │
 │  Headlamp UI server + API proxy                     │
 │  (forwards requests using service account token     │