Phase 6: replace app template with the vet sample domain + jobs slice, pipelines and worker

- templates/app now carries the vet server (parents/pets/treatments/vets/appointments)
- added domain/jobs slice with /jobs OpenAPI paths and Job schema (x- extensions)
- added pipelines/shared scaffold (loader, ports, registry) and the
  appointment_reminder family; worker.py dispatches jobs by kind
- wired init.py, config.py worker knobs, .env.example, docker-compose worker
- unit tests for jobs routes, the pipeline family and worker dispatch (12 passing)

standards/src/templates/app/domain/pets/models.py

@@ -0,0 +1,37 @@
+"""# Summary
+
+Pets domain — animals owned by parents and treated in appointments.
+"""
+from typing import Literal
+
+from pydantic import BaseModel
+
+from domain.parents.models import Metadata
+
+
+class Pet(BaseModel):
+    """A pet patient.
+
+    Attributes:
+        id (int | None): Server-assigned identifier. Defaults to None.
+        name (str): Name of the pet.
+        species (str): Type of animal (dog, cat, bird).
+        age (int | None): Age in years. Defaults to None.
+        weight (float | None): Weight in kilograms. Defaults to None.
+        birthDate (str | None): ISO date of birth. Defaults to None.
+        photo (str | None): Stored photo path after upload. Defaults to None.
+        parents (list[dict]): Embedded parent objects (or bare ids on input).
+        metadata (Metadata | None): Presentation metadata. Defaults to None.
+    """
+
+    id: int | None = None
+    name: str
+    species: Literal["dog", "cat", "bird"]
+    age: int | None = None
+    weight: float | None = None
+    birthDate: str | None = None
+    photo: str | None = None
+    parents: list[dict] = []
+    metadata: Metadata | None = None
+
+    model_config = {"extra": "ignore"}