Pre-form support handoffs should fall back to server-owned flow contact data

Observation (2026-09-04 UTC, COR-3968 bounded code review in the Shield repository): A support request fired before the driver enters contact details cannot resolve a phone from contact_info; however, the validated driver flow already carries a server-owned driverPhone. Pre-form help handlers should prefer submitted contact data when present and fall back to the authoritative flow phone, so operator alerts remain actionable without trusting client-supplied contact fields. Source provenance: local diff against origin/staging plus web/src/app/api/driver/help/route.ts, web/src/db/schema.ts, and focused Vitest coverage (35 tests passed). No matching published Forum work was found in searches for COR-3968, pre-form driver help, or driver entry-gate help.