Chart repository and docs site unreachable: cloudnative-pg.io has a lame delegation

**Title:** Chart repository and docs site unreachable: `cloudnative-pg.io` has a lame delegation

**Repo:** `cloudnative-pg/charts` (no issue templates there, so this is free-form; happy to move it if there is a better home for infrastructure reports)

---

### Summary

`https://cloudnative-pg.github.io/charts` currently 301-redirects to `https://cloudnative-pg.io/charts/index.yaml`, and `cloudnative-pg.io` does not resolve. The four nameservers the domain is delegated to answer `REFUSED`, so every resolver returns `SERVFAIL`.

This breaks the install command documented in `charts/cloudnative-pg/README.md`:

```console
helm repo add cnpg https://cloudnative-pg.github.io/charts
helm repo update
```

It also takes down the operator documentation site at `https://cloudnative-pg.io/`, so the scope is wider than the chart repository.

### Impact

Any `helm repo add` or `helm dependency update` against the documented URL fails. In CI this surfaces as:

```
...Unable to get an update from the "https://cloudnative-pg.github.io/charts" chart repository:
Get "https://cloudnative-pg.io/charts/index.yaml": dial tcp: lookup cloudnative-pg.io: server misbehaving
Error: no cached repository for helm-manager- found. (try 'helm repo update')
```

### Root cause evidence

The domain is **not** expired and the nameservers are **not** down — they are reachable and actively refusing the zone.

- **Registry (RDAP, `.io`)**: registered 2022-03-30, **expires 2027-03-30**, status `client transfer prohibited`. No hold or redemption status. Last changed **2026-08-11T20:33:55Z**.
- **Delegated nameservers**: `ns-455.awsdns-56.com`, `ns-1162.awsdns-17.org`, `ns-1622.awsdns-10.co.uk`, `ns-560.awsdns-06.net` — Amazon Route 53 (`205.251.19x.x`, per ARIN).
- **Google Public DNS**: `SERVFAIL`, comment `Name servers refused query (lame delegation?) [205.251.194.48, 205.251.193.199, 205.251.196.138, 205.251.198.86]`
- **Cloudflare**: `EDE(22): No Reachable Authority at delegation cloudnative-pg.io.` and `EDE(23): Network Error 205.251.194.48:53 returned REFUSED for cloudnative-pg.io NS`
- **DNSSEC ruled out**: no `DS` record is published, and querying with `CD=1` (validation disabled) fails identically.

Route 53 returns `REFUSED` for zones it does not host, which is consistent with the hosted zone having been deleted or recreated — a recreated zone is assigned a *different* NS set, leaving the registrar delegation pointing at the previous four. The `2026-08-11` registry change lines up with that window.

### Reproduction

```console
$ curl -sSI https://cloudnative-pg.github.io/charts/index.yaml | grep -i location
location: https://cloudnative-pg.io/charts/index.yaml

$ curl -sS "https://dns.google/resolve?name=cloudnative-pg.io&type=NS"
{"Status":2, ... "Comment":"Name servers refused query (lame delegation?) [...]"}

$ helm repo add cnpg https://cloudnative-pg.github.io/charts && helm repo update
```

### What still works

Worth noting, because it means no artifacts were lost:

- `https://raw.githubusercontent.com/cloudnative-pg/charts/gh-pages/index.yaml` returns **200** with 52 chart versions, and the `urls:` entries point at `https://github.com/cloudnative-pg/charts/releases/download/...`, which is reachable. Using that raw URL as a Helm repository works today (verified with `helm dependency update`).
- The OCI registry is healthy: `ghcr.io/cloudnative-pg/charts/cloudnative-pg:0.29.0` returns 200 and pulls fine.

So this looks purely like a DNS delegation problem rather than anything lost.

### Suggested fix

Either point the registrar's NS records at the current Route 53 hosted zone's assigned nameservers, or recreate the hosted zone for `cloudnative-pg.io` and re-delegate. Both the chart index and the documentation site should recover once the delegation is authoritative again.

If the move away from the GitHub Pages custom domain was intentional, it would help to update `charts/cloudnative-pg/README.md` to document the OCI location as the primary install path, since `helm repo add` cannot work while the custom domain is unresolvable.

### Notes

There is no existing issue for this that I could find in this repository. Reported from a CI pipeline that consumes the chart as a dependency; happy to provide more resolver traces if useful.

Start with charts/cloudnative-pg/README.md, then reproduce the redirect and DNS failure using the shown curl, Google Public DNS, and Helm commands. Check the Route 53 delegation and confirm that cloudnative-pg.io resolves, the docs site loads, and helm repo add cnpg https://cloudnative-pg.github.io/charts followed by helm repo update succeeds.

Written by the indexing model from the issue text.