Switch reqwest to rustls, bump Rust to 1.85

native-tls 0.2.17 fails to compile with Rust 1.84+ (TLSv1.3
exhaustive match). Using rustls avoids openssl dependency entirely.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Cargo.toml

@@ -5,7 +5,7 @@ edition = "2021"
 
 [dependencies]
 axum = { version = "0.7", features = ["multipart"] }
-reqwest = { version = "0.12", features = ["multipart", "json"] }
+reqwest = { version = "0.12", default-features = false, features = ["multipart", "json", "rustls-tls"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 tokio = { version = "1", features = ["full"] }