feat(sub-lang): Integrate SUB Language (.sb) native kernel modules and in-kernel VM/interpreter

- Add native .sb kernel modules in sub/ (signature.sb, power_governor.sb, benchmark.sb, easter_egg.sb)
- Implement in-kernel SUB Language VM and AST interpreter in kernel/sub/sub_vm.c
- Implement C-interop runtime in kernel/sub/sub_runtime.c and include/kernel/sub_lang.h
- Initialize SUB Language Engine in boot sequence step [8/14] in kernel/main.c
- Implement strtol in lib/string.c
- Add LazyBox applets: 'subinfo', 'subi', 'subpower', 'subbench', and 'subquote'

sub/benchmark.sb

@@ -0,0 +1,36 @@
+// Integer Matrix & Recursive Algorithm Benchmark
+// Written in SUB Language (.sb) - Simple Universal Builder
+
+function sub_fib(n) {
+    if n <= 1 {
+        return n
+    }
+    return sub_fib(n - 1) + sub_fib(n - 2)
+}
+
+function sub_matrix_multiply_test(dim) {
+    var total = 0
+    var i = 0
+    while i < dim {
+        var j = 0
+        while j < dim {
+            var k = 0
+            while k < dim {
+                total = total + (i * dim + k) * (k * dim + j)
+                k = k + 1
+            }
+            j = j + 1
+        }
+        i = i + 1
+    }
+    return total
+}
+
+function run_sub_lang_benchmark(iterations) {
+    var score = 0
+    var fib_result = sub_fib(15) // 610
+    var mat_result = sub_matrix_multiply_test(8)
+
+    score = fib_result + (mat_result % 1000) + (iterations * 10)
+    return score
+}