feat(web): UI component layer + dark-theme reskin

The TRM tokens were good but every screen hand-rolled inputs and buttons as
bare outlines on near-black panels, so fields, cards and buttons were
visually indistinguishable. Add a component layer (.input/.select/.textarea
as recessed slots, .btn family with a FILLED primary, .card scaffolding) and
adopt it across the booth/shift/login/tariff/site screens — several of which
were still light-theme inline styles dropped on a dark background.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/web/src/Login.tsx

@@ -23,37 +23,31 @@ export function Login({ onLoggedIn }: { onLoggedIn: (u: SessionUser) => void })
   }
 
   return (
-    <main style={{ fontFamily: "system-ui", maxWidth: 320, margin: "4rem auto" }}>
-      <h1>{t("auth.title")}</h1>
-      <form onSubmit={submit}>
-        <div style={{ margin: "0.5rem 0" }}>
-          <label>
-            {t("auth.username")}
-            <br />
-            <input
-              value={username}
-              onChange={(e) => setUsername(e.target.value)}
-              autoFocus
-              autoComplete="username"
-              style={{ width: "100%" }}
-            />
-          </label>
+    <main className="flex min-h-screen items-center justify-center bg-term-bg px-4">
+      <form onSubmit={submit} className="card w-full max-w-sm p-6">
+        <h1 className="mb-5 text-h5 font-semibold uppercase tracking-widest text-term-amber">{t("auth.title")}</h1>
+        <div className="field mb-3">
+          <label className="label">{t("auth.username")}</label>
+          <input
+            className="input"
+            value={username}
+            onChange={(e) => setUsername(e.target.value)}
+            autoFocus
+            autoComplete="username"
+          />
         </div>
-        <div style={{ margin: "0.5rem 0" }}>
-          <label>
-            {t("auth.password")}
-            <br />
-            <input
-              type="password"
-              value={password}
-              onChange={(e) => setPassword(e.target.value)}
-              autoComplete="current-password"
-              style={{ width: "100%" }}
-            />
-          </label>
+        <div className="field mb-3">
+          <label className="label">{t("auth.password")}</label>
+          <input
+            className="input"
+            type="password"
+            value={password}
+            onChange={(e) => setPassword(e.target.value)}
+            autoComplete="current-password"
+          />
         </div>
-        {error && <p style={{ color: "crimson" }}>{error}</p>}
-        <button type="submit" disabled={busy || !username || !password}>
+        {error && <p className="mb-3 text-[12px] text-term-red">{error}</p>}
+        <button type="submit" className="btn btn-primary btn-lg w-full" disabled={busy || !username || !password}>
           {busy ? t("auth.signingIn") : t("auth.signIn")}
         </button>
       </form>