feat: add authenticated engine processing boundary

site/services/engine.py

@@ -0,0 +1,46 @@
+"""Shared orchestration for the contract reconstruction engine.
+
+This module deliberately accepts the batch's persistence-backed extractor and
+dossier builder as dependencies. Both the browser workflow and the JSON
+integration boundary therefore execute the same business flow in-process,
+while tests can replace either dependency without constructing HTTP calls or
+making network requests.
+"""
+
+
+def analyze_batch(batch_id, documents, extractor, dossier_builder,
+                  progress_callback=None, llm_client=None):
+    """Extract document passports, assemble dossiers, and shape the API result.
+
+    `extractor` owns LLM interaction and persistence of each extraction;
+    `dossier_builder` consumes those saved passports and persists the resulting
+    graph. Keeping the calls in this order is an invariant: grouping must never
+    observe a partially extracted batch. The callback remains optional because
+    small batches run synchronously, while the existing large-batch route uses
+    it to update persistent progress.
+    """
+    extraction = extractor(
+        batch_id,
+        llm_client=llm_client,
+        progress_callback=progress_callback,
+        documents=documents,
+    )
+    dossier_result = dossier_builder(batch_id) if extraction.get("ok") else {"ok": False}
+    classes = extraction.get("classes", {})
+    math_checks_passed = sum(
+        1 for result in extraction.get("results", [])
+        if (result.get("extraction") or {}).get("math_validation", {}).get("status") == "VERIFIED"
+    )
+    return {
+        "ok": bool(extraction.get("ok")) and bool(dossier_result.get("ok")),
+        "v3": True,
+        "done": extraction.get("done", 0),
+        "total": len(documents),
+        "failed": extraction.get("failed", 0),
+        "classes": classes,
+        "ignored_accounting": classes.get("ignored_accounting", 0),
+        "math_checks_passed": math_checks_passed,
+        "dossier_count": len(dossier_result.get("dossiers", [])),
+        "ambiguous": dossier_result.get("ambiguous", 0),
+        "unlinked": dossier_result.get("unlinked", []),
+    }