Strictly parse numeric hardware parameters

[s2015-turtle]

Summary

• Validate complete finite numeric values and reject malformed or out-of-range integers before conversion.
• Bound CAN receive QoS depth to 1–4096.
• Preserve CAN ID/watchdog base notation and explicitly document whitespace and sign behavior.
• Include parameter and hardware/joint context in parsing failures.
• Add regression tests for malformed values, overflow, signs, whitespace, bases, and valid boundaries.

Validation

• git diff --check passed.
• Five-distro and vcan CI will validate builds and tests; no local ROS build performed.

Closes #32