feat: new session modal, status bar controls (Esc, C-m, close), sendRaw

- NewSessionModal with tabs: new session (agent + optional initial prompt)
  and resume existing (filterable by agent)
- Status bar: +new, Esc, Ctrl+M, terminal buttons; close with confirm
- sendRaw on EphemeralTerminal for raw control characters
- createNewSession accepts optional initialPrompt, auto-sent on ready

frontend/src/components/FloatingTranscriptDebug.vue

@@ -681,6 +681,7 @@ onBeforeUnmount(() => {
               @switch-agent="handleAgentSwitch"
               @select-session="handleSessionSelect"
               @create-session="handleCreateSession"
+              @close-session="closeTerminal"
               @start-recording="voice.startRecording()"
               @stop-recording="voice.stopRecording()"
               @set-voice-mode="voice.setMode($event)"