Alerts tab, Docker tab, nine new skins including HUD, a colour for every machine

Alerts: rules over sensors, watched fleet-wide from the hub; ntfy and webhook channels;
firing count on the rail. Docker: containers by stack with live use, start/stop/restart,
following logs, inspect, images/volumes/networks. Skins: HUD, Nord, Gruvbox, Catppuccin
(+Latte), Dracula, Tokyo Night, Solarized (+Light). Accents: per-machine colour.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

web/src/MachineSwitcher.tsx

@@ -1,6 +1,7 @@
 import { useEffect, useRef, useState } from 'react'
 import { MachineStatus } from './api'
 import { useEscape } from './ui'
+import { accentFor } from './accents'
 
 const hostOf = (url: string) => { try { return new URL(url).hostname } catch { return url } }
 
@@ -30,11 +31,11 @@ export default function MachineSwitcher({ hub, hubAddr, current, machines, onCha
       {open && (
         <div className="mmenu">
           <button className={'mitem' + (!current ? ' on' : '')} onClick={() => { setOpen(false); onChange(null) }}>
-            <span className="dot ok" /><span className="mname">{hub}</span><span className="muted small mono">{hubAddr || 'this host'}</span>
+            <span className="dot ok" /><span className="mname" style={{ color: accentFor(hub) }}>{hub}</span><span className="muted small mono">{hubAddr || 'this host'}</span>
           </button>
           {machines.map((m) => (
             <button key={m.name} className={'mitem' + (current === m.name ? ' on' : '')} onClick={() => { setOpen(false); onChange(m.name) }} title={m.error || m.url}>
-              <span className={'dot ' + dotFor(m)} /><span className="mname">{m.name}</span><span className="muted small mono">{hostOf(m.url)}{m.online ? '' : ' · offline'}</span>
+              <span className={'dot ' + dotFor(m)} /><span className="mname" style={{ color: accentFor(m.name) }}>{m.name}</span><span className="muted small mono">{hostOf(m.url)}{m.online ? '' : ' · offline'}</span>
             </button>
           ))}
           <button className="mitem manage" onClick={() => { setOpen(false); onManage() }}>+ manage machines…</button>