chore: cargo update + drop test counts from README

`cargo update` bumped a batch of transitive deps to their latest
patch releases — most notably:

- `rustls 0.23.38 -> 0.23.40` (the GitHub Dependabot advisory)
- `rustls-webpki 0.103.12 -> 0.103.13`
- `jni 0.21 -> 0.22` (transitive via trino-rust-client)
- `windows-sys` consolidated, removing the old 0.45/0.59 split
- `thiserror 1.0.69 -> 2.1.0` (transitive)
- `cc`, `flate2`, `getrandom`, `libc`, `mio`, `web-time` patch bumps

`cesu8 -> simd_cesu8` is a transitive dep swap from upstream.

`cargo build`, `cargo test --lib` (191 passed), `cargo clippy --all-
targets -- -D warnings`, `cargo fmt --check` all pass.

README: drop "~191 tests", "~30 tests", "10 tests" — accurate today,
guaranteed to drift the moment somebody adds a test. Section reads
the same prose-wise without them.

Author: lfrancke