Fix failing unit tests in GitHub Actions matrix

- Clojure: Use 'clojure' instead of 'clj -M' for standalone script
- Dart: Add proper pubspec.yaml with SDK environment constraint
- Julia: Install SHA package before running tests
- Lua: Use lua5.4 explicitly, add awk for portable HMAC output parsing
- Perl: Install libjson-perl and libwww-perl dependencies
- Bash: Make un.sh executable before test
- OCaml: Add str.cma and unix.cma for Str module support
- OCaml unit test: Remove Str dependency with pure string search

tests/unit/test_ocaml.ml

@@ -40,10 +40,12 @@ let starts_with prefix str =
   String.length str >= plen && String.sub str 0 plen = prefix
 
 let contains haystack needle =
-  try
-    let _ = Str.search_forward (Str.regexp_string needle) haystack 0 in
-    true
-  with Not_found -> false
+  let rec search i =
+    if i + String.length needle > String.length haystack then false
+    else if String.sub haystack i (String.length needle) = needle then true
+    else search (i + 1)
+  in
+  search 0
 
 let () =
   print_endline "\n=== Extension Mapping Tests ===";