feat(annotate): default VLM to Qwen3.6-35B-A3B-FP8

Match the production target used in examples/annotations/run_hf_job.py.
Per Scale Labs' dense-captioning ablations, model capacity dominates
prompt-engineering gains; defaulting to the larger model avoids
shipping a worst-tier configuration out of the box.

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

src/lerobot/annotations/steerable_pipeline/config.py

@@ -102,7 +102,7 @@ class VlmConfig:
     # ``openai`` talks to a local OpenAI-compatible server; the CLI
     # auto-spawns one when ``auto_serve=True``.
     backend: str = "openai"
-    model_id: str = "Qwen/Qwen2.5-VL-7B-Instruct"
+    model_id: str = "Qwen/Qwen3.6-35B-A3B-FP8"
 
     # OpenAI-compatible server endpoint; ``EMPTY`` works for local servers.
     api_base: str = "http://localhost:8000/v1"