Move the legacy /camera/* contract into its own reference page so the main MCAP layout doc can stay focused on current bundled and copy-layout behavior.
Document the compatibility model explicitly: legacy single-camera is operationally equivalent to one-camera copy when the effective camera label is treated as the literal `camera`.
Update the mcap_rgbd_example helper and recipe docs to accept legacy /camera/* inputs under that compatibility rule instead of rejecting them.
Namespace single-source zed_svo_to_mcap outputs with a derived camera label so one-camera exports use the same copy-layout topic shape as current multi-camera copy files.
Use the per-camera frame and pose reference identifiers for those single-source outputs, document copy as the current one-camera wire shape, and clarify that legacy /camera/* files are retained only as a legacy contract.
Add a small mcap_rgbd_example helper plus mcap_recipes guide for summarizing bundled/copy MCAPs and exporting one RGB/depth sample, and update the validator and viewer wording/behavior to match the bundled-vs-copy semantics.
crosstyan