migration: establish exact preserved app baseline

backend/jobs/registry.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from pathlib import Path
+
+from app_config import APP_DIR
+
+
+@dataclass(frozen=True)
+class JobDefinition:
+    job_id: str
+    schedule: str
+    input_date_policy: str
+    dependencies: tuple[str, ...]
+    lock_key: str
+    timeout_seconds: int
+    max_attempts: int
+    output_version: str
+
+
+class JobRegistry:
+    def __init__(self, definitions: tuple[JobDefinition, ...]) -> None:
+        self.definitions = definitions
+        self._by_id = {item.job_id: item for item in definitions}
+        if len(self._by_id) != len(definitions):
+            raise ValueError("Background job IDs must be unique")
+
+    @classmethod
+    def load(cls, path: Path | None = None) -> "JobRegistry":
+        config_path = path or APP_DIR / "config" / "jobs.config.json"
+        payload = json.loads(config_path.read_text(encoding="utf-8"))
+        definitions = tuple(
+            JobDefinition(
+                job_id=str(item["id"]),
+                schedule=str(item["schedule"]),
+                input_date_policy=str(item["input_date_policy"]),
+                dependencies=tuple(str(value) for value in item.get("dependencies") or []),
+                lock_key=str(item["lock_key"]),
+                timeout_seconds=max(1, int(item["timeout_seconds"])),
+                max_attempts=max(1, int(item["max_attempts"])),
+                output_version=str(item["output_version"]),
+            )
+            for item in payload.get("jobs") or []
+        )
+        if not definitions:
+            raise ValueError("Background job registry is empty")
+        return cls(definitions)
+
+    def get(self, job_id: str) -> JobDefinition:
+        try:
+            return self._by_id[job_id]
+        except KeyError as exc:
+            raise ValueError(f"Background job is not registered: {job_id}") from exc