feat(orbit): per-guest suggestion mute + global pending-cap setting

Two anti-spam knobs the host can dial during a live session:

1. Per-guest suggestion mute — Mic / MicOff toggle next to the
   kick/ban buttons in the participants popover. Symmetric (re-enable
   later). State lives in OrbitState.suggestionBlocked: string[]; the
   guest reads it and disables its own Suggest controls so the user
   sees a clear "muted" state instead of silent failures. Host-side
   sweep also drops their outbox entries as a safety net.

2. Max pending approvals cap — number input in the session-settings
   popover, default 0 (= unlimited so existing sessions are unaffected).
   When set, the host sweep stops folding new outbox entries into the
   approval list once the cap is reached. The OrbitQueueHead surfaces
   "X / Y pending" so guests can see when they're getting close.

State changes are additive on the wire — both fields are optional, with
parseOrbitState defaulting them, so older clients keep working.

evaluateOrbitSuggestGate() centralises the guest-side allow/block check
shared between useOrbitSongRowBehavior and the ContextMenu Add-to-Session
items, plus suggestOrbitTrack as a defensive last line.

i18n: en + de + fr + nl + zh + nb + ru + es.

Also fixes an earlier dedupe-key collision: the (user, trackId) cache
keys were missing their separator (NULL byte slipped in during the
previous patch), so two tracks could share a key and one of them
silently overwrite the other. Restored the space separator.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/OrbitSettingsPopover.tsx

@@ -82,6 +82,27 @@ export default function OrbitSettingsPopover({ anchorRef, onClose }: Props) {
         </span>
       </label>
 
+      <label className="orbit-settings-pop__row">
+        <div className="orbit-settings-pop__text">
+          <div className="orbit-settings-pop__label">{t('orbit.settingMaxPending')}</div>
+          <div className="orbit-settings-pop__hint">{t('orbit.settingMaxPendingHint')}</div>
+        </div>
+        <input
+          type="number"
+          min={0}
+          max={999}
+          step={1}
+          value={settings.maxPending ?? 0}
+          onChange={e => {
+            const raw = parseInt(e.target.value, 10);
+            const next = Number.isFinite(raw) && raw >= 0 ? Math.min(raw, 999) : 0;
+            void updateOrbitSettings({ maxPending: next });
+          }}
+          className="orbit-settings-pop__number"
+          aria-label={t('orbit.settingMaxPending')}
+        />
+      </label>
+
       <div className="orbit-settings-pop__row orbit-settings-pop__row--stacked">
         <div className="orbit-settings-pop__text">
           <div className="orbit-settings-pop__label">{t('orbit.settingShuffleInterval')}</div>