Fix precedents search + auto-update case parties

block_writer: _build_precedents_context now searches both
paragraph_embeddings (other decisions by Dafna) and case_law_embeddings
(precedent case law). Previously only searched document_chunks which
had no cross-case data. Now returns ~2400 chars from 3 other decisions.

processor: Step 1.6 auto-updates case appellants/respondents from
classifier results when they're empty. Prevents blank party fields.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/services/processor.py

@@ -57,6 +57,18 @@ async def process_document(document_id: UUID, case_id: UUID) -> dict:
             len(classification_result["parties"].get("respondents", [])),
         )
 
+        # Step 1.6: Update case parties if empty
+        if case_id and case:
+            parties = classification_result.get("parties", {})
+            updates = {}
+            if not case.get("appellants") and parties.get("appellants"):
+                updates["appellants"] = parties["appellants"]
+            if not case.get("respondents") and parties.get("respondents"):
+                updates["respondents"] = parties["respondents"]
+            if updates:
+                await db.update_case(case_id, **updates)
+                logger.info("Updated case parties: %s", updates)
+
         # Step 2: Chunk
         logger.info("Chunking document (%d chars)", len(text))
         chunks = chunker.chunk_document(text)