feat(train): Record has a card for each activity, its Start opening the sheet for it (ADR 0030, D60)

The Record tab shows a card per activity it records, the interval plans
below. A card's Start opens the Record sheet for that activity, which
keeps every other choice; the sheet no longer chooses the activity, and
so offers the plans and routes for it or for any. While a recording is
under way or waits to be saved, the cards wait, the bar leading back.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/train/halkyon_train_flutter/lib/l10n/app_de.arb

@@ -15,9 +15,7 @@
   "aboutTitle": "Über Halkyon Train",
 
   "homeRecordHint": "Zeichne eins im Tab Aufzeichnen auf.",
-  "recordAction": "Aufzeichnen",
   "recordBack": "Zurück zur Aufzeichnung",
-  "recordSheetTitle": "Training aufzeichnen",
   "activityRunning": "Laufen",
   "activityWalking": "Gehen",
   "activityHiking": "Wandern",
@@ -573,5 +571,6 @@
   "homeWeekTime": "Zeit",
   "homeWeekDistance": "Distanz",
   "homeWeekWorkouts": "Trainings",
-  "homeWeekDuration": "{hours, plural, =0{{minutes} Min.} other{{hours} Std. {minutes} Min.}}"
+  "homeWeekDuration": "{hours, plural, =0{{minutes} Min.} other{{hours} Std. {minutes} Min.}}",
+  "recordPlansHeading": "Intervallpläne"
 }