feat: add project-scoped operations

app/domain/schemas/scada.py

@@ -1,4 +1,6 @@
-from pydantic import BaseModel
+from datetime import datetime
+
+from pydantic import BaseModel, ConfigDict, Field
 
 
 class ScadaDeviceResponse(BaseModel):
@@ -17,3 +19,31 @@ class ScadaDeviceResponse(BaseModel):
     y: float | None = None
     longitude: float | None = None
     latitude: float | None = None
+
+
+class ScadaLatestReadingResponse(BaseModel):
+    """Latest persisted observation for one project SCADA device."""
+
+    model_config = ConfigDict(extra="forbid", allow_inf_nan=False)
+
+    device_id: str
+    device_type: str
+    measurement_unit: str
+    transmission_mode: str
+    transmission_frequency: str
+    observed_at: datetime | None = None
+    monitored_value: float | None = None
+    cleaned_value: float | None = None
+
+
+class ScadaLatestReadingsResponse(BaseModel):
+    """Bounded device page with each device's latest persisted observation."""
+
+    model_config = ConfigDict(extra="forbid", allow_inf_nan=False)
+
+    items: list[ScadaLatestReadingResponse]
+    total: int = Field(ge=0)
+    limit: int = Field(ge=1, le=500)
+    offset: int = Field(ge=0)
+    observed_count: int = Field(ge=0)
+    latest_observed_at: datetime | None = None