fix(parallel_gripper): rename variables for consistency

[AkshayArjun]

Description

Rename internal variables in parallel_gripper_controller for consistency
and clarity.

Relates to #1229

Is this user-facing behavior change?

Did you use Generative AI?

Yes, Claude (Anthropic) was used to help understand the codebase and
discuss the changes. The actual code changes were made manually.

Additional Information

This is the first of multiple PRs addressing the issues raised in #1229.
Each issue will be addressed in a separate PR as suggested by the maintainer.

[christophfroehlich]

As it is used now, it is basically always max_velocity and max_effort? But I'm also fine with the changes.

[codecov]

Codecov Report

❌ Patch coverage is 21.05263% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 85.13%. Comparing base (799f93e) to head (141a0c2).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...roller/parallel_gripper_action_controller_impl.hpp	21.05%	15 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2314      +/-   ##
==========================================
- Coverage   85.14%   85.13%   -0.02%     
==========================================
  Files         154      154              
  Lines       15417    15417              
  Branches     1334     1334              
==========================================
- Hits        13127    13125       -2     
- Misses       1797     1800       +3     
+ Partials      493      492       -1     

Flag	Coverage Δ
unittests	85.13% <21.05%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...roller/parallel_gripper_action_controller_impl.hpp	25.24% <21.05%> (ø)

... and 1 file with indirect coverage changes

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[AkshayArjun]

As it is used now, it is basically always max_velocity and max_effort? But I'm also fine with the changes.

You're right that these hold the user provided maximum velocity and effort constraints. The rename was done purely for naming consistency (problem #4) within the Commands struct alongside position_cmd_, and to prepare for (problem #5) where these values will be clamped against params_.max_effort and params_.max_velocity.

[christophfroehlich]

As it is used now, it is basically always max_velocity and max_effort? But I'm also fine with the changes.

You're right that these hold the user provided maximum velocity and effort constraints. The rename was done purely for naming consistency (problem #4) within the Commands struct alongside position_cmd_, and to prepare for (problem #5) where these values will be clamped against params_.max_effort and params_.max_velocity.

you are referencing to very old issues with #4 syntax ;)