implemented bypass logic

[Joschi3]

Summary

Adds a ~/bypass_safety_checks service (std_srvs/SetBool) to the Safety Position Controller that temporarily disables collision checks and relaxes joint limits. This is useful when driving the arm into folded positions that require intentional collisions.

Features:

• Service to enable/disable safety bypass mode
• Auto-timeout (default 60s) automatically re-enables safety checks
• Configurable joint limit tolerance (default 3%) during bypass
• Joint wrapping for continuous joints remains always active

New parameters:

• safety_bypass_timeout (default: 60.0s)
• safety_bypass_joint_limit_tolerance (default: 0.03)