Add a Quick Jump copy-to-clipboard section to the dashboard (#22)

The uid_-_target grammar-mode SSH command was documented in the README but
nowhere in the UI itself -- users had to remember/reconstruct the format by
hand. Adds a "Quick Jump" card with a one-click-copy command for the
interactive-picker form, plus a copy button on every row of "Hosts you can
reach" that copies the exact grammar-mode command for that specific host
(using the logged-in user's own uid, so it's ready to paste and run as-is).

conf.ssh.listenPort is now passed to the dashboard view so the command can
include the right -p flag when the SSH front door isn't on the default port
22 (theta-env, for example, exposes it on 2222).

Verified live: logged in as the local admin user, confirmed the Quick Jump
command and a per-host command both populate correctly and copy to the
clipboard (toast confirmation), and that the per-host command matches the
exact uid_-_target grammar the SSH server's parseUsername expects.

nodejs/routes/render.js

@@ -14,6 +14,10 @@ const values = {
 	titleIcon: conf.environment !== 'production' ? '<i class="fa-brands fa-dev"></i>' : '',
 	name: conf.name,
 	logo: conf.logo,
+	// The SSH front door's port -- the dashboard's "quick jump" copy buttons
+	// need this to build a real, working `ssh ...` command (the web UI and
+	// SSH front door share a hostname but not a port).
+	sshPort: (conf.ssh && conf.ssh.listenPort) || 22,
 	...buildInfo,
 };