feat(backend): implement postgres job queue

backend/jobs/admin.py

@@ -0,0 +1,18 @@
+from django.contrib import admin
+
+from jobs.models import Job, JobEvent
+
+
+@admin.register(Job)
+class JobAdmin(admin.ModelAdmin):
+    list_display = ("id", "type", "status", "priority", "attempts", "max_attempts", "locked_by", "available_at")
+    list_filter = ("status", "type")
+    search_fields = ("id", "type", "idempotency_key", "locked_by")
+    readonly_fields = ("created_at", "updated_at", "finished_at")
+
+
+@admin.register(JobEvent)
+class JobEventAdmin(admin.ModelAdmin):
+    list_display = ("id", "job", "type", "attempt", "worker_id", "created_at")
+    list_filter = ("type",)
+    search_fields = ("job__id", "worker_id", "message")