feat(journal): implement journal UI components

Introduce a complete set of journal components including:
- JournalPanel: main container with mobile/desktop support
- ConnectionBar: MQTT connection and session management
- StreamView and StreamMessage: message log and individual message cards
- ComposePanel: message composition with type selection
- DynamicForm: recursive form generator based on Zod schemas

src/components/journal/index.ts

@@ -33,3 +33,12 @@ export type {
   SessionMeta,
   SessionManifest,
 } from "../stores/journalStream";
+
+// UI components
+export { JournalPanel } from "./JournalPanel";
+export type { JournalPanelProps } from "./JournalPanel";
+export { ConnectionBar } from "./ConnectionBar";
+export { StreamView } from "./StreamView";
+export { StreamMessageCard } from "./StreamMessage";
+export { ComposePanel } from "./ComposePanel";
+export { DynamicForm } from "./DynamicForm";