fix(#240): remove CTA buttons and dead i18n keys from Mission Control Strip

The enrich page already handles task routing; the buttons in the
segmentation and transcription columns were redundant. Removes the
unused mission_control_segmentation_cta, mission_control_transcription_cta,
and mission_control_ready_all_cta keys from all three locale files.

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

frontend/messages/es.json

@@ -560,17 +560,14 @@
 	"mission_control_segmentation_heading": "Marcar regiones",
 	"mission_control_segmentation_description": "Marcar áreas de texto — sin conocimientos previos",
 	"mission_control_seg_skill_pill": "✓ Sin conocimientos previos",
-	"mission_control_segmentation_cta": "Empezar a marcar →",
 	"mission_control_segmentation_empty": "Todos los documentos ya tienen bloques de segmentación.",
 	"mission_control_transcription_heading": "Escribir el texto",
 	"mission_control_transcription_description": "Escribir el texto — conocimiento de Kurrent útil",
 	"mission_control_trans_skill_pill": "Kurrent útil",
-	"mission_control_transcription_cta": "Empezar a escribir →",
 	"mission_control_transcription_empty": "No hay documentos esperando transcripción.",
 	"mission_control_ready_heading": "Listo para leer ✓",
 	"mission_control_ready_description": "Completamente transcrito y revisado",
 	"mission_control_ready_subtitle": "{count} documentos listos",
-	"mission_control_ready_all_cta": "Leer todos ({count}) →",
 	"mission_control_ready_empty": "Aún no hay documentos completamente transcritos.",
 	"mission_control_ready_empty_cta": "Empezar a colaborar",
 	"mission_control_weekly_pulse": "↑ +{count} esta semana",