restructure: move el compiler content into lang/

lang/tests/text/examples/count-overlap-skip.el

@@ -0,0 +1,11 @@
+// count-overlap-skip.el — non-overlapping advance: "aaaa" / "aa" -> 2.
+// After each match, the cursor advances by len(sub), so overlapping matches
+// are skipped. This is the universal default in C/Python/Go/etc.
+fn run_test() -> Int {
+    let s: String = "aaaa"
+    return str_count(s, "aa")
+}
+
+fn main() -> Void {
+    println(int_to_str(run_test()))
+}