feat: route email notifications through mail capability

src/govoplan_notifications/backend/schemas.py

@@ -6,7 +6,17 @@ from typing import Any, Literal
 from pydantic import BaseModel, ConfigDict, Field, field_validator
 
 
-NotificationStatus = Literal["pending", "queued", "sending", "sent", "failed", "skipped", "cancelled"]
+NotificationStatus = Literal[
+    "pending",
+    "queued",
+    "sending",
+    "accepted",
+    "paused",
+    "sent",
+    "failed",
+    "skipped",
+    "cancelled",
+]
 
 
 def normalize_notification_action_url(value: str | None) -> str | None:
@@ -154,6 +164,8 @@ class NotificationDeliveryResultResponse(BaseModel):
     notification: NotificationResponse | None = None
     processed: int = 0
     sent: int = 0
+    accepted: int = 0
+    paused: int = 0
     failed: int = 0
     skipped: int = 0
     errors: list[str] = Field(default_factory=list)