review fixes: light-mode contrast, tz robustness, deploy copy

- admin: maroon buttons use .danger class (white text); replace hardcoded
  #333/#ff8a8a/drop-target colors with theme vars so light mode is legible
- time.ts: force hourCycle h23 (no 24:00 artifact), drop dead 24-guard
- Makefile/README: rsync with excludes instead of `cp -a .` so .git and the
  dev DB don't ship to /opt; add rsync to deps

client/src/admin/Admin.tsx

@@ -62,7 +62,7 @@ function Login({ onAuthed }: { onAuthed: () => void }) {
           value={pw}
           onInput={(e: any) => setPw(e.currentTarget.value)}
         />
-        {err && <div style="color:#ff8a8a">{err}</div>}
+        {err && <div style="color:var(--danger)">{err}</div>}
         <button type="submit">Anmelden</button>
       </div>
     </form>
@@ -107,7 +107,7 @@ function Stats() {
     <>
       <div class="row" style="justify-content: space-between">
         <h2 style="margin:0">Umsatz nach Tagen</h2>
-        <button onClick={reset} style="background:#5a2a2a; border-color:#7a3a3a">Statistik zurücksetzen</button>
+        <button class="danger" onClick={reset}>Statistik zurücksetzen</button>
       </div>
       <table>
         <thead><tr><th>Tag</th><th>Transaktionen</th><th>Bezahlt</th><th>Crew-Transaktionen</th><th>Pfand zurück</th></tr></thead>
@@ -227,7 +227,7 @@ function Drinks() {
                   <button onClick={() => patch(d.id, { archived: !d.archived } as any)}>
                     {d.archived ? 'aktivieren' : 'archivieren'}
                   </button>
-                  <button onClick={() => del(d)} style="background:#5a2a2a; border-color:#7a3a3a">löschen</button>
+                  <button class="danger" onClick={() => del(d)}>löschen</button>
                 </div>
               </td>
             </tr>
@@ -377,7 +377,7 @@ function Bars() {
     <>
       <h2>Bars</h2>
       {bars.map(b => (
-        <div key={b.id} style="margin-bottom:16px; padding:8px; border:1px solid #333; border-radius:6px">
+        <div key={b.id} style="margin-bottom:16px; padding:8px; border:1px solid var(--border); border-radius:6px">
           <div class="row">
             <label>
               Name
@@ -397,7 +397,7 @@ function Bars() {
                 }
               />
             </label>
-            <button onClick={() => delBar(b)} style="background:#5a2a2a; border-color:#7a3a3a; margin-left:auto">Tresen löschen</button>
+            <button class="danger" onClick={() => delBar(b)} style="margin-left:auto">Tresen löschen</button>
           </div>
           <BarDrinkEditor
             bar={b}