Fix macOS build: vendor OpenSSL, improve release asset names

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/Cargo.lock

@@ -1141,6 +1141,15 @@ version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d05e27ee213611ffe7d6348b942e8f942b37114c00cc03cec254295a4a17852e"
 
+[[package]]
+name = "openssl-src"
+version = "300.5.5+3.5.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3f1787d533e03597a7934fd0a765f0d28e94ecc5fb7789f8053b1e699a56f709"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "openssl-sys"
 version = "0.9.111"
@@ -1149,6 +1158,7 @@ checksum = "82cab2d520aa75e3c58898289429321eb788c3106963d0dc886ec7a5f4adc321"
 dependencies = [
  "cc",
  "libc",
+ "openssl-src",
  "pkg-config",
  "vcpkg",
 ]