fix: handle documents as list or dict in prompt builder

EspoCRM may send documents as a list instead of a dict with
totalFiles. Convert list to dict format to avoid AttributeError.

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

api/services/prompt_builder.py

@@ -65,6 +65,8 @@ def build_case_prompt(context: dict) -> str:
     recent_notes = context.get("recentNotes", [])
     templates = context.get("availableTemplates", [])
     documents = context.get("documents", {})
+    if isinstance(documents, list):
+        documents = {"totalFiles": len(documents)}
     recent_calls = context.get("recentCalls", [])
     case_memory = context.get("caseMemory", {})
     assistant_rules = context.get("assistantRules", [])