fix(i18n): add missing marketplace.accessDenied and translate calendar form

- Add marketplace.accessDenied to de.json and en.json
- Add 12 calendar form field/action keys to widgets.calendar in both locales
- Replace all hardcoded English strings in calendar-source-form.tsx with t() calls
- Remove locale-detection hack on Cancel button (was comparing t() result to English string)

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

apps/web/src/components/settings/calendar-source-form.tsx

@@ -83,16 +83,16 @@ export function CalendarSourceForm({
     try {
       const parsed = new URL(value);
       if (parsed.protocol !== 'https:') {
-        setUrlError('URL must use HTTPS protocol');
+        setUrlError(t('calendar.formUrlErrorHttps'));
         return false;
       }
       setUrlError('');
       return true;
     } catch {
-      setUrlError('Invalid URL format');
+      setUrlError(t('calendar.formUrlErrorInvalid'));
       return false;
     }
-  }, []);
+  }, [t]);
 
   // Form is valid when name, type, and url are filled and url is https
   const isFormValid =
@@ -136,7 +136,7 @@ export function CalendarSourceForm({
       {/* Name */}
       <div>
         <label htmlFor="source-name" className="mb-1 block text-sm text-foreground">
-          Name *
+          {t('calendar.formFieldName')} *
         </label>
         <input
           id="source-name"
@@ -151,7 +151,7 @@ export function CalendarSourceForm({
       {/* Type */}
       <div>
         <label htmlFor="source-type" className="mb-1 block text-sm text-foreground">
-          Type *
+          {t('calendar.formFieldType')} *
         </label>
         <select
           id="source-type"
@@ -176,7 +176,7 @@ export function CalendarSourceForm({
             htmlFor="exchange-mode"
             className="mb-1 block text-sm text-foreground"
           >
-            Exchange Mode
+            {t('calendar.formFieldExchangeMode')}
           </label>
           <select
             id="exchange-mode"
@@ -196,7 +196,7 @@ export function CalendarSourceForm({
       {/* URL */}
       <div>
         <label htmlFor="source-url" className="mb-1 block text-sm text-foreground">
-          URL *
+          {t('calendar.formFieldUrl')} *
         </label>
         <input
           id="source-url"
@@ -228,7 +228,7 @@ export function CalendarSourceForm({
             htmlFor="source-username"
             className="mb-1 block text-sm text-foreground"
           >
-            Username
+            {t('calendar.formFieldUsername')}
           </label>
           <input
             id="source-username"
@@ -247,7 +247,7 @@ export function CalendarSourceForm({
             htmlFor="source-password"
             className="mb-1 block text-sm text-foreground"
           >
-            Password
+            {t('calendar.formFieldPassword')}
           </label>
           <input
             id="source-password"
@@ -261,7 +261,7 @@ export function CalendarSourceForm({
 
       {/* Color */}
       <div>
-        <label className="mb-1 block text-sm text-foreground">Color</label>
+        <label className="mb-1 block text-sm text-foreground">{t('calendar.formFieldColor')}</label>
         <div className="flex gap-2">
           {SOURCE_COLOR_PALETTE.map((c) => (
             <button
@@ -288,14 +288,14 @@ export function CalendarSourceForm({
           disabled={!isFormValid || isSaving}
           className="rounded bg-primary px-4 py-2 text-sm font-medium text-primary-foreground transition-colors hover:bg-primary/90 disabled:opacity-50 disabled:cursor-not-allowed"
         >
-          {isSaving ? 'Saving...' : 'Save'}
+          {isSaving ? t('calendar.formSaving') : t('calendar.formSave')}
         </button>
         <button
           type="button"
           onClick={onCancel}
           className="rounded border border-border px-4 py-2 text-sm text-foreground transition-colors hover:bg-muted"
         >
-          {t('calendar.addSource') === 'Add source' ? 'Cancel' : 'Abbrechen'}
+          {t('calendar.formCancel')}
         </button>
       </div>
     </form>