fix: switch reqwest TLS backend from rustls to native-tls

reqwest 0.13 defaults to rustls -> aws-lc-rs which requires cmake/nasm
in minimal build environments (AUR chroot). Switch all direct reqwest
users to native-tls (system OpenSSL) to fix clean chroot build failures
reported by users.

Affected crates: owlry-core, owlry-lua, owlry-rune
PKGBUILD: add openssl to depends for all three runtime packages
Also add scripts/aur-local-test for clean chroot testing workflow

crates/owlry-lua/Cargo.toml

@@ -31,7 +31,7 @@ serde_json = "1.0"
 semver = "1"
 
 # HTTP client for plugins
-reqwest = { version = "0.13", features = ["blocking", "json"] }
+reqwest = { version = "0.13", default-features = false, features = ["native-tls", "blocking", "json"] }
 
 # Math expression evaluation
 meval = "0.2"