Upgrade roslibrust_transforms to transforms v2.1

[deniz-hofmeister]

Description

Upgrades roslibrust_transforms from transforms v1.2 to v2.1 and adapts to its new API.

Breaking changes

• Static transforms are now represented by Stamp::Static instead of a magic zero timestamp. On the wire they are still stamped with time zero.
• Transforms are built with Transform::new(...) / Transform::static_between(...) instead of struct literals, and fields are accessed via methods (translation(), rotation(), parent(), child(), timestamp()). Construction is fallible, so non-unit quaternions and NaN/infinite components are caught up front.
• update_static_transform() is removed. add_transform() now routes by the transform's stamp: Stamp::At publishes to /tf, Stamp::Static publishes to /tf_static. The registry is updated before publishing, so a transform the registry rejects (e.g. one that would re-parent a frame) is never sent to other nodes; rejection surfaces as a new TransformManagerError::RejectedTransform.
• IntoTransform::into_transform now returns Result<Transform, TransformError>.
• Stamp, TimeError, TimePoint, and TransformError are re-exported alongside the existing types.

New features

• latest_common_time(target, source) — the tf2-style "latest available transform" lookup, returning Stamp::At(time) or Stamp::Static for purely static chains.
• remove_frame(frame) — drops a frame from the local buffer, providing an escape hatch for re-parenting (the transforms crate rejects a child appearing under a new parent otherwise).

Robustness fixes

• Invalid or registry-rejected transforms received over /tf / /tf_static are dropped with a warning instead of silently corrupting the buffer (v1.2's infallible add_transform made this impossible to detect).
• Pre-epoch ROS timestamps (negative sec) are clamped to zero rather than wrapping, since Timestamp is unsigned nanoseconds.
• Waiter notification switched from a broadcast channel to a watch channel, so notifications coalesce and lagged-receiver handling disappears.
• Read-only lookups (get_transform, get_transform_at, wait_for_transform checks) take a read lock instead of a write lock, since v2 registry lookups no longer require &mut.

Housekeeping

• Dropped the now-unused chrono dependency.
• Updated the examples and README to the new API.
• New tests: pre-epoch clamping, invalid transforms dropped, static publish routing to /tf_static, latest_common_time, and re-parenting rejected until remove_frame is called.

🤖 Generated with Claude Code

[deniz-hofmeister]

Hey @Carter12s ,

I recently released a v2 of my transforms library, so I would like to propose this PR to update your transforms version to v2. Please have a look.

Things that improved over v1 is an API overhaul with greatly improved Error reporting.