fix: Preserve case in question IDs during parsing

Problem: Parser converted question IDs to lowercase ('qAnalyst' → 'qanalyst'),
causing normalization to fail because id_catalog lookup is case-sensitive.

Impact: All workflow question signals were lost - normalized_signals stayed empty,
so template placeholders like {{node_2.signal_qAnalyst}} remained unresolved.

Solution: Removed .lower() call in parse_decision_questions() to preserve
original case from AI response.

Root cause: Line 162 in result_container_parser.py
Fixes: Question augmentation signals not appearing in workflow end nodes

backend/result_container_parser.py

@@ -158,7 +158,8 @@ def parse_decision_questions(section_text: str) -> Dict[str, str]:
     for pattern in patterns:
         matches = re.finditer(pattern, section_text, re.MULTILINE | re.IGNORECASE)
         for match in matches:
-            question_type = match.group(1).strip().lower()
+            # Preserve original case for question IDs (e.g., "qAnalyst" not "qanalyst")
+            question_type = match.group(1).strip()
             answer = match.group(2).strip()
 
             # Entferne Klammern und Whitespace