Support PEP 440 SDK release gate and trusted publishing

[manas-fortifyroot]

Summary

• Support PEP 440 RC and final tags.
• Dispatch SDK release-gate runs to fr-system-tests.
• Keep public-bound dispatcher minimal: no private backend target reads.
• Update manual publish workflow for SHA checkout, gate-status verification, version/tag validation, TestPyPI/PyPI environment separation, and trusted publishing.

Validation

• actionlint on touched workflows passed.
• Workflow YAML parse checks passed.
• git diff --check passed.