feat(NSPasteboard): added objective c bridge and build changes

src/Clip/NSPasteboard.zig

@@ -0,0 +1,18 @@
+const std = @import("std");
+
+extern fn sendPB(text: [*:0]const u8) void;
+extern fn initPB() void;
+
+test "objc bridge" {
+    initPB();
+    sendPB("test_string");
+
+    const result = try std.process.run(std.testing.allocator, std.testing.io, .{
+        .argv = &.{"pbpaste"},
+    });
+    defer std.testing.allocator.free(result.stdout);
+    defer std.testing.allocator.free(result.stderr);
+
+    try std.testing.expectEqualStrings("test_string", std.mem.trim(u8, result.stdout, "\n"));
+}
+