fix: guard aux LLM calls against None content + reasoning fallback + retry (salvage #3389) (#3449)

Salvage of #3389 by @binhnt92 with reasoning fallback and retry logic added on top.

All 7 auxiliary LLM call sites now use extract_content_or_reasoning() which mirrors the main agent loop's behavior: extract content, strip think blocks, fall back to structured reasoning fields, retry on empty.

Closes #3389.

agent/auxiliary_client.py

@@ -1616,6 +1616,62 @@ def call_llm(
         raise
 
 
+def extract_content_or_reasoning(response) -> str:
+    """Extract content from an LLM response, falling back to reasoning fields.
+
+    Mirrors the main agent loop's behavior when a reasoning model (DeepSeek-R1,
+    Qwen-QwQ, etc.) returns ``content=None`` with reasoning in structured fields.
+
+    Resolution order:
+      1. ``message.content`` — strip inline think/reasoning blocks, check for
+         remaining non-whitespace text.
+      2. ``message.reasoning`` / ``message.reasoning_content`` — direct
+         structured reasoning fields (DeepSeek, Moonshot, Novita, etc.).
+      3. ``message.reasoning_details`` — OpenRouter unified array format.
+
+    Returns the best available text, or ``""`` if nothing found.
+    """
+    import re
+
+    msg = response.choices[0].message
+    content = (msg.content or "").strip()
+
+    if content:
+        # Strip inline think/reasoning blocks (mirrors _strip_think_blocks)
+        cleaned = re.sub(
+            r"<(?:think|thinking|reasoning|REASONING_SCRATCHPAD)>"
+            r".*?"
+            r"</(?:think|thinking|reasoning|REASONING_SCRATCHPAD)>",
+            "", content, flags=re.DOTALL | re.IGNORECASE,
+        ).strip()
+        if cleaned:
+            return cleaned
+
+    # Content is empty or reasoning-only — try structured reasoning fields
+    reasoning_parts: list[str] = []
+    for field in ("reasoning", "reasoning_content"):
+        val = getattr(msg, field, None)
+        if val and isinstance(val, str) and val.strip() and val not in reasoning_parts:
+            reasoning_parts.append(val.strip())
+
+    details = getattr(msg, "reasoning_details", None)
+    if details and isinstance(details, list):
+        for detail in details:
+            if isinstance(detail, dict):
+                summary = (
+                    detail.get("summary")
+                    or detail.get("content")
+                    or detail.get("text")
+                )
+                if summary and summary not in reasoning_parts:
+                    reasoning_parts.append(summary.strip() if isinstance(summary, str) else str(summary))
+
+    if reasoning_parts:
+        return "\n\n".join(reasoning_parts)
+
+    return ""
+
+
 async def async_call_llm(
     task: str = None,
     *,