security(deps): lockfile bumps clearing open Cargo advisories (Track E)

Lockfile-only (cargo update -p; Cargo.toml untouched):
  openssl  0.10.76 -> 0.10.80  (clears GHSA-8c75/ghm9/hppc/phqj/pqf5/xmgf/xp3w/xv59)
  rand     0.9.2   -> 0.9.3    (RUSTSEC-2026-0097 / GHSA-cq8v-f236-94qc)
  thin-vec 0.2.14  -> 0.2.16   (RUSTSEC-2026-0103 / GHSA-xphw-cqx3-667j)

Clears the live Dependabot Rust advisories on this repo (docmatrix#21, Track E).
Same recipe as 007 #44. Residual RUSTSEC unmaintained-crate advisories
(ansi_term/yaml-rust/bincode/rustls-pemfile) are NOT vulnerabilities and need
dep removal/replacement separately.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: hyperpolymath