Run Data pre-query scripts before dispatch

[czyt]

Summary

• Run the isolated pre-query script before each Data query, including SQL and variable changes.
• Preserve cancellation, query identity, read-only admission, and privacy boundaries across preparation and dispatch.
• Add server, protocol, browser, and database regressions.

Verification

• Application CI run 38887284349: source, checks, release server build, and three-database job succeeded.
• Local focused tests and 390px Chinese/English browser flow completed on this branch.