fix(#240): rename segmentation column heading to "Text markieren"

"Rahmen einzeichnen" assumed familiarity with the segmentation concept;
"Text markieren" is self-explanatory for new contributors.

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

frontend/messages/de.json

@@ -559,7 +559,7 @@
 	"training_chip_kurrent": "Kurrent-Erkennung",
 	"training_chip_segmentation": "Segmentierung",
 	"mission_control_heading": "Was braucht Aufmerksamkeit?",
-	"mission_control_segmentation_heading": "Rahmen einzeichnen",
+	"mission_control_segmentation_heading": "Text markieren",
 	"mission_control_segmentation_description": "Textbereiche markieren — keine Vorkenntnisse nötig",
 	"mission_control_seg_skill_pill": "✓ Ohne Vorkenntnisse",
 	"mission_control_segmentation_empty": "Alle Dokumente haben bereits Segmentierungsblöcke.",

frontend/messages/en.json

@@ -559,7 +559,7 @@
 	"training_chip_kurrent": "Kurrent recognition",
 	"training_chip_segmentation": "Segmentation",
 	"mission_control_heading": "What needs attention?",
-	"mission_control_segmentation_heading": "Draw regions",
+	"mission_control_segmentation_heading": "Mark text",
 	"mission_control_segmentation_description": "Mark text areas — no prior knowledge needed",
 	"mission_control_seg_skill_pill": "✓ No prior knowledge",
 	"mission_control_segmentation_empty": "All documents already have segmentation blocks.",

frontend/messages/es.json

@@ -559,7 +559,7 @@
 	"training_chip_kurrent": "Reconocimiento Kurrent",
 	"training_chip_segmentation": "Segmentación",
 	"mission_control_heading": "¿Qué necesita atención?",
-	"mission_control_segmentation_heading": "Marcar regiones",
+	"mission_control_segmentation_heading": "Marcar texto",
 	"mission_control_segmentation_description": "Marcar áreas de texto — sin conocimientos previos",
 	"mission_control_seg_skill_pill": "✓ Sin conocimientos previos",
 	"mission_control_segmentation_empty": "Todos los documentos ya tienen bloques de segmentación.",

frontend/src/lib/components/MissionControlStrip.svelte.spec.ts

@@ -54,7 +54,7 @@ describe('MissionControlStrip', () => {
 			}
 		});
 
-		await expect.element(page.getByText('Rahmen einzeichnen')).toBeInTheDocument();
+		await expect.element(page.getByText('Text markieren')).toBeInTheDocument();
 		await expect.element(page.getByText('Text eintippen')).toBeInTheDocument();
 		await expect.element(page.getByText(/Lesefertig/)).toBeInTheDocument();
 	});