dead-code: remove unused cutterDropHint locale key (DE+EN)

The static.cutterDropHint entry (DE: "Video-Datei hierher ziehen zum Laden.", EN: "Drop a video file here to load it.") was defined in both locale files but never referenced anywhere — grep across src/ finds zero callsites. Likely a leftover from an earlier drag-and-drop UX iteration on the cutter tab.

Removed both entries. tsc + smoke + full E2E still green.

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

src/renderer-locale-de.ts

@@ -182,7 +182,6 @@ const UI_TEXT_DE = {
         streamerBulkRemoveTitle: 'Alle entfernen (oder gefilterte)',
         streamerBulkRemoveAll: 'Alle {count} Streamer aus der Liste entfernen?',
         streamerBulkRemoveFiltered: 'Die {count} passenden Streamer aus der Liste entfernen?',
-        cutterDropHint: 'Video-Datei hierher ziehen zum Laden.',
         metadataCacheMinutesLabel: 'Metadata-Cache (Minuten)',
         filenameTemplatesTitle: 'Dateinamen-Templates',
         vodTemplateLabel: 'VOD-Template',

src/renderer-locale-en.ts

@@ -182,7 +182,6 @@ const UI_TEXT_EN = {
         streamerBulkRemoveTitle: 'Remove all (or filtered)',
         streamerBulkRemoveAll: 'Remove all {count} streamers from the list?',
         streamerBulkRemoveFiltered: 'Remove the {count} matching streamer(s) from the list?',
-        cutterDropHint: 'Drop a video file here to load it.',
         metadataCacheMinutesLabel: 'Metadata Cache (Minutes)',
         filenameTemplatesTitle: 'Filename Templates',
         vodTemplateLabel: 'VOD Template',