docs(node): warn QueryNodes truncates without next_key + add isActiveStatus helper

[Sentinel-Bluebuilder]

Summary

Two chain v3 footguns that bite consumers on day 1. This PR addresses both with the smallest possible surface area: JSDoc warnings + one tiny exported helper.

1. QueryNodes / QueryNodesForPlan return next_key=null on truncation

Sentinel chain v3 does not emit pagination.next_key for these queries even when results are truncated. Consumers writing the obvious `while (next_key)` loop silently drop nodes.

Reproducible against mainnet:

```bash
curl 'https://lcd.sentinel.co/sentinel/node/v3/plans/36/nodes?pagination.limit=500'
| jq '{count: (.nodes | length), next: .pagination.next_key}'

=> { "count": 500, "next": null }

curl 'https://lcd.sentinel.co/sentinel/node/v3/plans/36/nodes?pagination.offset=500&pagination.limit=500'
| jq '.nodes | length'

=> 303 (so plan 36 actually has 803 nodes; the first call hid 303 of them)

```

The fix is pure JSDoc — direct callers to use a large `limit` or `offset`-based pagination instead of trusting `next_key`.

2. Status comes in three shapes — add an `isActiveStatus` helper

Subscription / session / node status is emitted as:

• `"STATUS_ACTIVE"` in LCD JSON
• numeric `1` over RPC
• typed `Status.STATUS_ACTIVE` enum after ts-proto decode

Consumers who pick one shape and forget the others get silent zero results when their data source changes (e.g., switching from LCD to RPC). 10-line helper in `utils.ts`:

```ts
export function isActiveStatus(s: string | number | Status): boolean {
return s === Status.STATUS_ACTIVE || s === "STATUS_ACTIVE" || s === 1;
}
```

Strictly opt-in. No existing call site changes. `statusFromJSON` from the generated proto already handles the same conversion, but it lives in `protobuf/` and consumers don't typically reach there — this exposes the equivalent check from the public utils surface.

Test plan

• `npx tsc --noEmit` passes
• No runtime behavior change (JSDoc + new export only)
• `isActiveStatus` returns true for all three shapes; false for inactive variants