chore(deps): bump rustls to 0.23.45 (GHSA-2mjx-qc3c-rqvc) (#124)

## Summary

Fixes Dependabot alert #2 (GHSA-2mjx-qc3c-rqvc, medium): rustls `>=
0.23.13, < 0.23.45` accepts TLS 1.3 handshake messages across encryption
level boundaries.

- `rustls` 0.23.40 → 0.23.45 (patched)
- `rustls-webpki` 0.103.13 → 0.103.15 (rustls 0.23.44+ requires
`^0.103.14`)
- `tempfile` now resolves `getrandom 0.3.4` instead of `0.4.2` (cargo
re-resolution side effect; dev/test tooling only)

`Cargo.lock` only. `rustls` is a transitive dependency via `reqwest`,
and every dependent's requirement (`^0.23`, `^0.23.4`, `^0.23.27`)
already allows 0.23.45, so no manifest changes were needed.

## Why not Dependabot

The Dependabot security job failed with `security_update_not_possible`
(latest-resolvable `0.23.43`, no conflicting dependencies). 0.23.43 is
the last rustls compatible with the locked `rustls-webpki` 0.103.13, and
Dependabot did not move that second crate. `cargo update -p rustls
--precise 0.23.45` resolves both together.

## Test plan

- [x] `cargo clippy --all-targets -- -D warnings`
- [x] `cargo test --all-targets`
- [ ] CI

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Co-authored-by: Claude Sonnet 5.5 <noreply@anthropic.com>

Author: jpage-godaddy