feat(ui): highlight user chat messages + opt-in interrupt (stop) button

LogKindForegroundConverter drives the log message foreground via a local
binding (beats the dim local value), so user messages render in the accent
color instead of vanishing into the transcript. Adds a small stop (Icon.Stop)
button next to Send in both composers (SessionTerminalView + WorkConsole) wired
to InterruptInteractiveCommand → InterruptInteractiveSessionAsync. Adds
session.composer.interrupt (en/de).

src/ClaudeDo.Localization/locales/de.json

@@ -235,7 +235,8 @@
     "composer": {
       "placeholder": "Nachricht an die Sitzung…",
       "send": "Senden",
-      "stop": "Sitzung beenden"
+      "stop": "Sitzung beenden",
+      "interrupt": "Aktuellen Zug unterbrechen"
     }
   },
   "missionControl": {