feat(robots): natively integrate Seeed Studio reBot B601-DM arm (#3624)

* feat(robots): natively integrate Seeed Studio reBot B601-DM arm

Add first-class LeRobot support for the Seeed Studio reBot arm, replacing
the out-of-tree `lerobot-robot-seeed-b601` / `lerobot-teleoperator-rebot-arm-102`
plugin packages.

New devices:
- robot `rebot_b601_follower` — single-arm B601-DM follower (6-DOF + gripper,
  Damiao CAN motors via `motorbridge`)
- robot `bi_rebot_b601_follower` — bimanual follower composing two single arms
- teleoperator `rebot_102_leader` — single-arm StarArm102 / reBot Arm 102 leader
  (FashionStar UART servos via `motorbridge-smart-servo`)
- teleoperator `bi_rebot_102_leader` — bimanual leader composing two single arms

The bimanual variants reuse the single-arm classes and namespace each arm's
observation/action keys with `left_` / `right_` prefixes, so a bimanual
StarArm102 leader can teleoperate a bimanual reBot B601 follower.

Optional SDK imports are guarded; a `rebot` extra installs `motorbridge` and
`motorbridge-smart-servo`.

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

* docs: add reBot B601-DM calibration & dual-arm teleoperation guide

Add docs/source/rebot_b601.mdx covering single-arm and bimanual
calibration and teleoperation for the reBot B601-DM follower and
reBot Arm 102 leader, with zero-position reference images from the
Seeed Studio wiki. Register the page in the docs toctree.

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

* docs: fix reBot B601 MDX build (move JSON example out of <Tip>)

The doc-builder parses `{...}` inside MDX component children as a
Svelte expression, so the joint_directions JSON example broke the
build. Move it into a top-level fenced code block.

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

* docs: apply prettier formatting to reBot B601 page

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

* docs: remove duplicate colocated reBot B601 page

docs/source/rebot_b601.mdx is the canonical, toctree-registered page;
the colocated rebot_b601.md was a redundant thinner copy.

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

* docs: clarify 6-DOF leader fallback comment in reBot B601 follower

Explain that holding wrist_yaw at zero is what lets a 6-DOF leader
(e.g. so100_leader / so101_leader) teleoperate the 7-DOF follower.

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

* refactor: address Caroline's PR review on reBot B601 integration

- leader: remove _validate_config (no other lerobot device validates its
  config; a key mismatch now surfaces as a plain KeyError)
- leader: simplify _round_to_valid_range to direct modular arithmetic
  instead of a bidirectional search loop
- leader: inline the single-use _clamp helper
- follower & leader: write MotorCalibration range_min/range_max from the
  configured joint_limits / joint_ranges instead of a fixed [-90, 90]
- docs: add a "Find the USB ports" section (lerobot-find-port) and move
  the brltty/permissions tip there; link the OpenArm page for SocketCAN
  adapter configuration

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

---------

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

pyproject.toml

@@ -151,6 +151,8 @@ pyserial-dep = ["pyserial>=3.5,<4.0"]
 deepdiff-dep = ["deepdiff>=7.0.1,<9.0.0"]
 pynput-dep = ["pynput>=1.7.8,<1.9.0"]
 pyzmq-dep = ["pyzmq>=26.2.1,<28.0.0"]
+motorbridge-dep = ["motorbridge>=0.3.2,<0.4.0"]
+motorbridge-smart-servo-dep = ["motorbridge-smart-servo>=0.0.4,<0.1.0"]
 
 # Motors
 feetech = ["feetech-servo-sdk>=1.0.0,<2.0.0", "lerobot[pyserial-dep]", "lerobot[deepdiff-dep]"]
@@ -174,6 +176,9 @@ unitree_g1 = [
     "lerobot[pygame-dep]",
 ]
 reachy2 = ["reachy2_sdk>=1.0.15,<1.1.0"]
+# Seeed Studio reBot B601-DM follower (motorbridge / CAN) + StarArm102 / reBot Arm 102
+# leader (motorbridge-smart-servo / FashionStar UART servos).
+rebot = ["lerobot[motorbridge-dep]", "lerobot[motorbridge-smart-servo-dep]"]
 kinematics = ["lerobot[placo-dep]"]
 intelrealsense = [
     "pyrealsense2>=2.55.1.6486,<2.57.0 ; sys_platform != 'darwin'",
@@ -260,6 +265,7 @@ all = [
     "lerobot[lekiwi]",
     "lerobot[openarms]",
     "lerobot[reachy2]",
+    "lerobot[rebot]",
     "lerobot[kinematics]",
     "lerobot[intelrealsense]",
     "lerobot[diffusion]",