Share server submit option parsing

[jolovicdev]

Summary

• Move server submit option parsing into a shared helper used by sync and async handlers
• Keep the existing submit defaults for cache, tags, retries, force, timeout, and ttl
• Add server coverage for explicit cache: false

Testing

• .venv/bin/ruff check src/ tests/
• .venv/bin/pytest tests/ -q

[ds-review]

DS-Review

No blocking issues found.

Reviewed the changed diff and related call paths. No actionable bugs, security issues, or meaningful performance regressions were found.

[jolovicdev]

Closing this as part of cleanup for temporary DS-Reviewer test branches. This PR was opened only for reviewer-bot scenario testing, not for merge.