bugfix speech-to-text and implement avatar and personal greeting

backend/app/schemas.py

@@ -66,6 +66,12 @@ class InstructionOut(BaseModel):
     model_config = {"from_attributes": True}
 
 
+# ── Dashboard ────────────────────────────────────────────────────────
+class DashboardOut(BaseModel):
+    username: str
+    latest_instruction_at: datetime | None = None
+
+
 # ── Chat ──────────────────────────────────────────────────────────────
 class ChatMessage(BaseModel):
     role: str  # "user" | "assistant"