Pair hosts when they start instead of in the installer

The installer only writes the controller URL and host name. Running the
host requests to join the cluster if it has not been approved yet, or if
the controller no longer accepts its token, and waits until an admin
approves it. Once approved it saves its id and token and starts as
normal. A rejected host exits with code 8.

clusteriohost run --user-token approves the host right away with the
token of a user allowed to approve hosts. The token is not saved.

This moves the pairing client into the host package, where it uses the
same certificate setup as the host's connection to the controller, and
removes --no-pair and the rerun handling from the installer.

scripts/version-compat-test.js

@@ -32,8 +32,6 @@ import readline from "node:readline";
 import util from "node:util";
 
 import { loadBreaks, matchBreaks, selectBreaks } from "./version-compat-breaks.js";
-// Only uses Node builtins, so it does not load a second copy of the lib.
-import { pairHost, PairingError } from "../packages/create/pair.js";
 
 const execFile = util.promisify(child_process.execFile);
 
@@ -294,16 +292,20 @@ async function pairHostWithController() {
 	const ctlConfig = JSON.parse(await fs.readFile(path.join(controllerDir, "config-ctl.json"), "utf8"));
 	const controllerUrl = ctlConfig["ctl.controller_url"];
 	console.log(`| pairing host with ${controllerUrl}`);
-	let pairing;
-	try {
-		pairing = await pairHost({ controllerUrl, name: "host", token: ctlConfig["ctl.controller_token"] });
-	} catch (err) {
-		if (err instanceof PairingError && err.status === 404) {
-			console.log("| controller does not support host pairing");
-			return false;
-		}
-		throw err;
+	// A user allowed to approve hosts gets the host straight away, without waiting for approval.
+	const response = await fetch(new URL("api/host-pairing", controllerUrl), {
+		method: "POST",
+		headers: { "Content-Type": "application/json", "Authorization": `Bearer ${ctlConfig["ctl.controller_token"]}` },
+		body: JSON.stringify({ name: "host" }),
+	});
+	if (response.status === 404) {
+		console.log("| controller does not support host pairing");
+		return false;
 	}
+	if (response.status !== 200) {
+		throw new Error(`Pairing host failed with ${response.status}: ${await response.text()}`);
+	}
+	const pairing = await response.json();
 	console.log(`| paired host ${pairing.name} with id ${pairing.hostId}`);
 
 	// The same fields the installer sets, which every host version reads.