Merge branch 'main' into feat/language-annotation-pipeline

Resolves conflicts from 32 commits on main:

* docs/source/_toctree.yml — keep both new toc entries
  (annotation_pipeline + video_encoding_parameters).
* docs/source/language_and_recipes.mdx — adopt main's section
  ordering (Layer 2 before "Temporal semantics") and float32
  timestamp dtype to match the codebase.
* src/lerobot/configs/__init__.py — keep both export sets
  (recipe + video encoder).
* src/lerobot/datasets/dataset_metadata.py — drop redundant lazy
  imports (top-level imports cover both LANGUAGE_COLUMNS and
  DEFAULT_TOOLS); adopt main's @tools.setter for info.json
  write-back.
* src/lerobot/datasets/feature_utils.py — call the real
  validate_feature_language() instead of returning "".
* src/lerobot/datasets/language.py — float32 timestamps to match
  pa.float32() used in video_utils.py and the rest of the codebase.
* src/lerobot/datasets/language_render.py — adopt main's
  unwrap_scalar() helper (drops two hand-rolled .item()/list
  unwrappers); float32 in docstring.
* src/lerobot/processor/render_messages_processor.py — drop
  PR-local _scalar() helper, use shared unwrap_scalar().
* tests/datasets/test_language.py — adopt main's new float32 dtype
  + validate_feature_language warning tests.
* tests/datasets/test_dataset_metadata.py — adopt main's new
  tools.setter persist/clear tests.
* uv.lock — regenerated cleanly from main's resolver.

90 of 92 touched tests pass. Two pre-existing test failures
(test_module1_plan_memory_subtask_smoke,
test_module2_mid_episode_emits_paired_interjection_and_speech in
tests/annotations/test_modules.py) are unrelated to this merge —
that test file doesn't exist on main, so the failures originate on
the branch and are addressed by the 8 newer fix(annotate) commits
already on origin that will land in a follow-up.

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

tests/fixtures/dataset_factories.py

@@ -46,7 +46,6 @@ from tests.fixtures.constants import (
     DUMMY_MOTOR_FEATURES,
     DUMMY_REPO_ID,
     DUMMY_ROBOT_TYPE,
-    DUMMY_VIDEO_INFO,
 )
 
 
@@ -134,9 +133,7 @@ def features_factory():
         use_videos: bool = True,
     ) -> dict:
         if use_videos:
-            camera_ft = {
-                key: {"dtype": "video", **ft, **DUMMY_VIDEO_INFO} for key, ft in camera_features.items()
-            }
+            camera_ft = {key: {"dtype": "video", **ft} for key, ft in camera_features.items()}
         else:
             camera_ft = {key: {"dtype": "image", **ft} for key, ft in camera_features.items()}
         return {