fix: share _safe_json_loads with tool-call parser, not just orchestrator

Move _safe_json_loads from orchestrator.py to llm_client.py and have
_extract_tool_calls use it when parsing <tool_call> JSON blocks from
model output. orchestrator now imports it from llm_client.

Background: in the first full DeepSeek run (runs/2026-05-12T17-25-38),
~10 'Failed to parse tool call JSON' warnings appeared, all from regex
patterns where the LLM wrote \. or \* inside JSON string values:

  Failed to parse tool call JSON: {..., "pattern": "Outlook Express|...|\.dbx"}
  Failed to parse tool call JSON: {..., "pattern": "ethereal.*\.pcap"}
  Failed to parse tool call JSON: {..., "pattern": "lookatlan.*\.txt|..."}

These are exactly the kind of stray-backslash errors stage-1 sanitize
already handles for orchestrator JSON calls — but tool-call extraction
was using bare json.loads. Result: each failed tool call silently dropped
on the floor, the LLM never got a result, and at least one network agent
burned 14m26s spinning before hitting max_iterations=40.

Now the sanitize/log-on-failure path is shared. Verified against the
three failure cases from yesterday's log: all three now parse cleanly.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

llm_client.py

@@ -80,6 +80,36 @@ def _build_tools_prompt(tools: list[dict]) -> str:
     return "\n".join(lines)
 
 
+def _safe_json_loads(text: str):
+    """Parse JSON with progressive sanitization for LLM-produced output.
+
+    Tries (0) as-is, (1) escape stray backslashes outside valid JSON escapes
+    (\\" \\\\ \\/ \\b \\f \\n \\r \\t \\uXXXX). On final failure, logs raw
+    input (first 600 chars) so we can diagnose what the model emitted.
+
+    Used both by orchestrator JSON callsites and by _extract_tool_calls
+    when parsing <tool_call> blocks from model output.
+    """
+    try:
+        return json.loads(text)
+    except json.JSONDecodeError:
+        pass
+
+    stage1 = re.sub(
+        r'\\(?!["\\/bfnrt]|u[0-9a-fA-F]{4})',
+        r'\\\\',
+        text,
+    )
+    try:
+        return json.loads(stage1)
+    except json.JSONDecodeError as e:
+        logger.warning(
+            "_safe_json_loads failed after sanitize (%s); raw head[:600]=%r",
+            e, text[:600],
+        )
+        raise
+
+
 def _extract_tool_calls(text: str) -> list[dict]:
     """Extract tool call JSON blocks from model output."""
     pattern = re.compile(
@@ -90,7 +120,7 @@ def _extract_tool_calls(text: str) -> list[dict]:
     for match in pattern.finditer(text):
         raw = match.group(1).strip()
         try:
-            parsed = json.loads(raw)
+            parsed = _safe_json_loads(raw)
             calls.append(parsed)
         except json.JSONDecodeError:
             logger.warning("Failed to parse tool call JSON: %s", raw[:200])