Build one ClientConfig that names ring and loads the native roots once, and hand it to every tokio-tungstenite dial as its connector instead of installing a process-wide default from the dial path. Each of the three dial sites gets a wss:// test that reproduces the panic if its connector is dropped.
The two tests that shipped with the fix both called ensure_crypto_provider
themselves, so deleting the call from connect_upstream left the whole suite
green, and swapping ring for aws-lc-rs did too.
Adds an integration test, which gets its own process, that dials wss:// at a
local plain-TCP listener through the public Responses WebSocket entrypoint and
asserts an Err plus an installed provider. Without the install in the dial it
panics with the original CryptoProvider message. A unit test now compares the
installed provider's cipher suites and key-exchange groups against ring's, so
the choice of backend is pinned rather than assumed.
Also names tls12 in the workspace rustls features: it already arrives through
reqwest and tokio-rustls, so the graph is unchanged, but a direct dependency
should say it needs TLS 1.2 rather than inherit it.
