feat: add batch MCAP export tooling for ZED segments

Add a Python batch wrapper around zed_svo_to_mcap for multi-camera
segment exports. The new script supports dataset discovery, repeated
segment-dir inputs, CSV-driven ordering, skip/probe/report flows, dry-run,
and CUDA environment passthrough so kindergarten-style datasets can be
converted into one bundled MCAP per segment.

Extend zed_svo_to_mcap so bundled multi-camera mode accepts --end-frame
with synced-group semantics. In this mode the value is interpreted as the
last emitted synced frame-group index from the common synced start, while
--start-frame remains unsupported.

Vendor a minimal pose-config TOML and a sample segments CSV into this repo
so the MCAP workflow is self-contained. Update the README to document the
batch MCAP flow, use portable placeholders instead of machine-specific
absolute paths, and describe the expected dataset layout explicitly.

config/zed_pose_config.toml

@@ -0,0 +1,18 @@
+# Minimal pose-tracking config for zed_svo_to_mcap.
+# The converter currently reads only:
+#   - zed.coordinate_system
+#   - zed.body_tracking.reference_frame
+#   - zed.body_tracking.set_floor_as_origin
+
+[zed]
+# Native ZED 3D/body coordinate system used when reading positional tracking.
+# Supported values in this repo are IMAGE and RIGHT_HANDED_Y_UP.
+coordinate_system = "IMAGE"
+
+[zed.body_tracking]
+# Reference frame used for per-camera pose estimation.
+# Supported values are CAMERA and WORLD.
+reference_frame = "CAMERA"
+
+# When true, WORLD origin is placed on the floor during positional tracking.
+set_floor_as_origin = false