Add Persona type definition with metadata fields

src/lib/types/Persona.ts

@@ -0,0 +1,10 @@
+export interface Persona {
+	id: string; // UUID
+	name: string;
+	occupation: string;
+	stance: string;
+	prompt: string; // The full system prompt text
+	isDefault: boolean; // True for built-in personas
+	createdAt: Date;
+	updatedAt: Date;
+}