feat(train): a recording under way above the bar on every tab, and a saved one opens its page (ADR 0030, D60)

halkyon_ui's NavigationFrame takes a status, standing above the floating
bar below medium windows and at the foot of the screen's panel from there
on. Train's RecordingBar fills it while a recording runs or waits to be
saved: its activity, moving time and distance, paused or stopped, a tap
back to it. Saving now opens the workout's page in Home's tab.

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_en.arb

@@ -714,5 +714,8 @@
   "settingsTitle": "Settings",
   "settingsTraining": "Training",
   "settingsVersion": "Version {version} (build {build})",
-  "@settingsVersion": {"placeholders": {"version": {"type": "String"}, "build": {"type": "String"}}}
+  "@settingsVersion": {"placeholders": {"version": {"type": "String"}, "build": {"type": "String"}}},
+  "recordingBarStopped": "Stopped: save or discard it",
+  "recordingBarDistance": "{km} km",
+  "@recordingBarDistance": {"placeholders": {"km": {"type": "String"}}}
 }