json-native: token positions (line/column); escape utils BMP coverage + surrogate guard; add smokes for string escapes, nested, and error cases (AST/VM)

docs/guides/examples/README.md

@@ -8,7 +8,7 @@ How to run (after full build):
   - `copyFrom = { method_id = 7, args = [ { kind = "box", category = "plugin" } ] }`
   - `cloneSelf = { method_id = 8 }`
 - Build the plugin: `cd plugins/nyash-filebox-plugin && cargo build --release`
-- Run the example: `./target/release/nyash docs/examples/plugin_boxref_return.nyash`
+- Run the example: `./target/release/nyash docs/guides/examples/plugin_boxref_return.nyash`
 
 Expected behavior:
 - Creates two FileBox instances (`f`, `g`), writes to `f`, copies content to `g` via `copyFrom`, then closes both.

docs/private/papers/reference/plugin-system/boxref-behavior.md

@@ -49,5 +49,4 @@
 ## 7. 参考
 - 仕様: `docs/reference/plugin-system/nyash-toml-v2_1-spec.md`
 - 実装: `src/runtime/plugin_loader_v2.rs`（引数検証/Handle戻り値復元）
-- 例: `docs/examples/plugin_boxref_return.nyash`
-
+- 例: `docs/guides/examples/plugin_boxref_return.nyash`

docs/reference/plugin-system/boxref-behavior.md

@@ -49,5 +49,4 @@
 ## 7. 参考
 - 仕様: `docs/reference/plugin-system/nyash-toml-v2_1-spec.md`
 - 実装: `src/runtime/plugin_loader_v2.rs`（引数検証/Handle戻り値復元）
-- 例: `docs/examples/plugin_boxref_return.nyash`
-
+- 例: `docs/guides/examples/plugin_boxref_return.nyash`