feat(interactive): host task-based ConPTY sessions in Command Center

Adds an 'Open ConPTY session' entry that fetches a task's launch spec and hosts
an embedded ConPTY terminal as a Mission Control pane, coexisting with the
streamed-log monitor panes (streaming stack untouched). Introduces IMissionControlPane
+ ConPtyPaneViewModel, a non-destructive Panes mirror (Monitors prefix + ConPtySessions
suffix) so unrelated monitor churn never tears down a live terminal, and a grid<->tabs
layout toggle. Launch failures surface via the footer error strip.

src/ClaudeDo.Localization/locales/de.json

@@ -129,6 +129,7 @@
     "ctxMarkDone": "Erledigt",
     "ctxMarkCancelled": "Abgebrochen",
     "ctxRunInteractively": "Interaktiv ausführen",
+    "ctxOpenConPtySession": "ConPTY-Sitzung öffnen",
     "ctxPickUpInTerminal": "Im Terminal fortsetzen",
     "ctxOpenPlanningSession": "Planungssitzung öffnen",
     "ctxResumePlanningSession": "Planungssitzung fortsetzen",
@@ -267,6 +268,10 @@
     "settings": "Einstellungen",
     "queue": "Warteschlange",
     "blocked": "Blockiert",
+    "focusMode": "Fokus",
+    "overviewMode": "Übersicht",
+    "closeSession": "Sitzung schließen",
+    "conptyLaunchFailed": "ConPTY-Sitzung konnte nicht geöffnet werden: {0}",
     "question": {
       "title": "Claude fragt nach",
       "placeholder": "Antwort eingeben…",