feat: add goreleaser config for cross-platform releases

Set up GoReleaser with Rust builder (cargo-zigbuild) targeting
linux/darwin x amd64/arm64, Gitea release publishing, and Homebrew
cask generation. Add mise tasks for test, release, and snapshot builds.

crates/gitnow/Cargo.toml

@@ -39,9 +39,11 @@ termwiz = "0.23.0"
 regex = "1.11.1"
 minijinja = "2"
 shell-words = "1"
+openssl = { version = "0.10", features = ["vendored"], optional = true }
 
 [dev-dependencies]
 pretty_assertions = "1.4.0"
 
 [features]
 example = []
+vendored-openssl = ["openssl/vendored"]