chore: bump internal node to 22 and standardise (#4084)

Bumps the internal/toolchain Node version to the latest 22.x LTS
(`22.23.1`) and standardises it across the repo. Scope is the **platform
toolchain + the repo's own runtime images** (all `20 → 22` *upgrades*,
off the now-EOL node 20).

### Main changes
- Node `20.20.2 → 22.23.1` across all CI workflows, `.nvmrc`,
`CONTRIBUTING.md`, and the OSS `docker/Dockerfile` (digest-pinned).
- `@types/node → 22.20.0` (root dep + pnpm `overrides`, so the whole
workspace resolves to it); lockfile regenerated.
- `sdk-compat` matrix: adds Node 24 + 26 (keeps 20, still in `engines`).
- **App runtime images → node 22** (were on EOL node 20):
`apps/coordinator` → `node:22.23.1-bookworm-slim`;
`apps/docker-provider` + `apps/kubernetes-provider` → `node:22-alpine`
(reusing the exact digest `apps/supervisor` already runs, so all four
worker images are now identical). Stage aliases renamed off `node-20`.

### Possible issues / test notes
- `@types/node` 22.x can surface new TS errors — typecheck (now on 22)
is the gate.
- **Smoke-test the v3 worker path** — `coordinator` (`crictl`/CRI calls)
and the docker/kubernetes providers (talking to their daemons) now run
on node 22 (alpine/musl for the providers). Upgrade off EOL so low-risk,
but it's deployed runtime code with its own `publish-worker.yml`
pipeline.

packages/python/package.json

@@ -49,7 +49,7 @@
     "tinyexec": "^0.3.2"
   },
   "devDependencies": {
-    "@types/node": "20.14.14",
+    "@types/node": "^22.20.0",
     "rimraf": "6.0.1",
     "tshy": "^3.0.2",
     "typescript": "^5.5.4",