Phase 10.7/10.5c: include cycle detection (VM/Interpreter), minimal pyc IR→Nyash, String unification bridge (VM partial), add core plugins: RegexBox/EncodingBox/TOMLBox/PathBox + examples; wire nyash.toml; begin String interop for internal vs plugin boxes; update CURRENT_TASK.md

examples/encoding_min.nyash

@@ -0,0 +1,8 @@
+static box Main {
+  main() {
+    local e = new EncodingBox()
+    local b64 = e.base64Encode("hello")
+    // quick check: "hello" -> aGVsbG8=
+    return b64.length() == 8
+  }
+}