Adds a pre-dispatch validation pass inside both agentic tool loops
(generate_chat_completion_with_tools in core/inference/llama_cpp.py and
run_safetensors_tool_loop in core/inference/safetensors_agentic.py).
The pass catches two failure modes between parser and dispatch:
* Unknown tool name (not in the request's tools[] array).
* Arguments that cannot decode to a JSON object when auto_heal is off.
On a caught call the loop appends a corrective tool-result message
tied to the hallucinated tool_call_id (not a fabricated id, so the
OpenAI chat template stays valid) and re-enters the model. When the
call has no usable id we fall back to a user-role correction since
tool-role messages require a matching prior call id.
The retry pass is bounded by max_validation_retries (default 2, new
ChatCompletionRequest field, threaded through the route layer). On
budget exhaustion the call falls through to the existing per-tool
error path so today's behavior is preserved.
When auto_heal_tool_calls is on the heal path still runs in the
dispatch loop unchanged; F3 only catches the strict-shape failures
the coercer cannot fix.
