Robot.get_manipulator_info silently overrides tcp_frame resolution

[jf---]

Problem

Robot.get_manipulator_info() in src/tesseract_robotics/planning/core.py:407-440 silently invents a tcp_frame when none is provided:

if tcp_frame is None:
    group = self.env.getKinematicGroup(group_name)
    tcp_frame = list(group.getActiveLinkNames())[-1]

In C++, ManipulatorInfo is a plain data struct — tcp_frame is an explicit required parameter in the constructor. The planner is responsible for frame resolution. This Python wrapper does resolution too early, hiding it behind a convenience API.

Issues

1. Hides a decision the user should make explicitly — grabbing the last active link is a heuristic that works for serial chains but breaks for branching kinematic trees
2. Hardcodes working_frame="base_link" — another silent assumption
3. Caches the guess — once auto-detected for a group, the result is cached and can't be corrected for the same (group, None, working_frame) key

Proposed fix

Make tcp_frame required (no default None), matching the C++ API's intent. Remove the auto-detect heuristic. Users should know which frame they're targeting.

[jf---]

@Levi-Armstrong can you advise on the canonical method to retrieve a TCP? This is an area where the bindings aren't particularly clear, though I strongly suspect I'm going about this in a highly convoluted manner.

How TCP is retrieved via tesseract is non obvious to me, since depending on URDF conventions and whether you're retrieving the flange or the tool TCP. Would you be so kind to point me in the right direction? This is a part of tesseract that I struggle with. Thanks in advance!