fix(native): domains-section flat, mails-section collapsible only

DomainSection bekommt collapsible-Prop (default false).
Domains-Section: kein Chevron, kein useState, Content immer sichtbar.
Mails-Section: collapsible={true} + open/onToggle wie bisher.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/rebreak-native/app/(app)/blocker.tsx

@@ -61,8 +61,6 @@ export default function BlockerScreen() {
   }, [refreshDomains, syncBlocklist, refresh]);
   useDomainSubmissionRealtime(onDomainChange, true);
 
-  // Section collapse state — beide Sections starten offen
-  const [webOpen, setWebOpen] = useState(true);
   const [mailOpen, setMailOpen] = useState(true);
 
   // AddSheet state: tracks which section opened it
@@ -369,8 +367,6 @@ export default function BlockerScreen() {
               title={t('blocker.section_domains')}
               count={countsByType.web}
               max={limits.web}
-              open={webOpen}
-              onToggle={() => setWebOpen((v) => !v)}
               onAdd={() => openAddSheet('web')}
               atLimit={countsByType.web >= limits.web}
             >
@@ -388,6 +384,7 @@ export default function BlockerScreen() {
               title={t('blocker.section_mails')}
               count={countsByType.mail}
               max={limits.mail}
+              collapsible
               open={mailOpen}
               onToggle={() => setMailOpen((v) => !v)}
               onAdd={() => openAddSheet('mail')}
@@ -448,7 +445,8 @@ function DomainSection({
   title,
   count,
   max,
-  open,
+  collapsible = false,
+  open = true,
   onToggle,
   onAdd,
   atLimit,
@@ -457,8 +455,9 @@ function DomainSection({
   title: string;
   count: number;
   max: number;
-  open: boolean;
-  onToggle: () => void;
+  collapsible?: boolean;
+  open?: boolean;
+  onToggle?: () => void;
   onAdd: () => void;
   atLimit: boolean;
   children: React.ReactNode;
@@ -496,8 +495,8 @@ function DomainSection({
     >
       {/* Section Header */}
       <TouchableOpacity
-        onPress={onToggle}
-        activeOpacity={0.7}
+        onPress={collapsible ? onToggle : undefined}
+        activeOpacity={collapsible ? 0.7 : 1}
         style={{
           flexDirection: 'row',
           alignItems: 'center',
@@ -521,14 +520,16 @@ function DomainSection({
             {t('blocker.count_label', { count, max })}
           </Text>
         </View>
-        <Ionicons
-          name={open ? 'chevron-up' : 'chevron-down'}
-          size={16}
-          color={colors.textMuted}
-        />
+        {collapsible && (
+          <Ionicons
+            name={open ? 'chevron-up' : 'chevron-down'}
+            size={16}
+            color={colors.textMuted}
+          />
+        )}
       </TouchableOpacity>
 
-      {open && (
+      {(!collapsible || open) && (
         <View style={{ paddingHorizontal: 14, paddingBottom: 14, gap: 12 }}>
           {/* Progressbar */}
           <View