Bug bash fixes: special-file reads, per-client lockout, prefs validation, security headers, kernel-thread guard, login feedback, error text; plus journal-quiet sudoers + journal groups, upload overwrite guard, machines pattern, dnf freshness, cron/services speed, clean version

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

web/src/Machines.tsx

@@ -96,7 +96,7 @@ export default function Machines({ hub, onChanged, onOpen }: { hub: Me; onChange
 
       <div className="dash-bar"><h2 className="section">Add a machine</h2></div>
       <form className="card addform" onSubmit={add}>
-        <label>Name <input value={name} onChange={(e) => setName(e.target.value)} placeholder="grid" pattern="[a-z0-9][a-z0-9-]*" required /></label>
+        <label>Name <input value={name} onChange={(e) => setName(e.target.value)} placeholder="grid" pattern="[a-z0-9][a-z0-9\\-]*" required /></label>
         <label>Address <input value={url} onChange={(e) => setUrl(e.target.value)} placeholder="https://10.0.0.214:8100" required /></label>
         <label>Its Ham Lab password <input type="password" value={pw} onChange={(e) => setPw(e.target.value)} autoComplete="off" required /></label>
         {addErr && <div className="error">{addErr}</div>}