reqwest was pinned to rustls-tls, so HTTPS only trusted the bundled
webpki roots: SSL_CERT_FILE, SSL_CERT_DIR, and the system CA store were
ignored, and obscura-net exposes no add-CA hook. Deployments behind a
TLS-inspecting egress proxy or an internal CA cannot fetch at all, and a
caching proxy in front of --proxy cannot terminate TLS.
Enable rustls-tls-native-roots alongside rustls-tls. reqwest merges the
two root stores into one, so the default trust surface only grows and
certificate verification is otherwise unchanged: unknown CAs are still
rejected. The stealth (wreq) client has its own TLS stack and is out of
scope here.
Tests: an in-process HTTPS fixture with an rcgen-minted private CA,
served via tokio-rustls (pinned to the ring provider so the test binary
has a single rustls CryptoProvider). With SSL_CERT_FILE pointing at the
CA the fetch succeeds; without it the same fixture is rejected.
Fixes#525.
