chore(v→zig): delete stale vendored V files from verisimdb subtree (#27)

Per estate-wide owner directive (2026-05-28). This repo carries a
vendored copy of verisimdb. After verisimdb#66 deleted the V-lang
v-api-gateway and api/v shims in the canonical source, the vendored
copies here are stale — the upstream is now Zig-only at
ffi/zig/ + connectors/clients/zig/.

Deletes:
* verisimdb/api/v/verisimdb.v
* verisimdb/v-api-gateway/  (full tree: README.adoc + src/main.v)

Surfaced via GitHub linguist estate-wide V-detection (12137 bytes of
V here despite the verisimdb canonical cleanup).

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath