json: add v2 JsonDoc/JsonNode plugin with runtime provider switch; vendored yyjson + FFI; loader resolve(name)->method_id; PyVM JSON shims; smokes + CI gate; disable MiniVmPrints fallbacks by default

- plugin_loader_v2: store per-Box resolve() from TypeBox FFI; add resolve_method_id() and use in invoke_instance_method
- plugin_loader_unified: resolve_method() falls back to loader’s resolve when TOML lacks method entries
- nyash.toml: register JsonDocBox/JsonNodeBox methods (birth/parse/root/error; kind/get/size/at/str/int/bool)
- plugins/nyash-json-plugin:
  * serde/yyjson provider switch via env NYASH_JSON_PROVIDER (default serde)
  * vendored yyjson (c/yyjson) + shim; parse/root/get/size/at/str/int/bool implemented for yyjson
  * TLV void returns aligned to tag=9
- PyVM: add minimal JsonDocBox/JsonNodeBox shims in ops_box.py (for dev path)
- tests/smokes: add jsonbox_{parse_ok,parse_err,nested,collect_prints}; wire two into min-gate CI
- tools: collect_prints_mixed now uses JSON-based app
- MiniVmPrints: move BinaryOp and fallback heuristics behind a dev toggle (default OFF)
- CURRENT_TASK.md: updated with provider policy and fallback stance

plugins/nyash-json-plugin/c/yyjson/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2020 YaoYuan <ibireme@gmail.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

plugins/nyash-json-plugin/c/yyjson_shim.c

@@ -0,0 +1,74 @@
+// Minimal shim to keep build/link path ready for a future yyjson backend.
+// This file does not currently implement parsing; the Rust side still
+// uses serde_json for actual parsing until the real yyjson integration lands.
+
+#include <stdint.h>
+#include <stddef.h>
+#include "yyjson/yyjson.h"
+
+// Parse JSON via yyjson and return 0 on success; non-zero error code on failure.
+int nyash_json_shim_parse(const char *text, size_t len) {
+    yyjson_read_err err;
+    yyjson_doc *doc = yyjson_read_opts(text, len, 0, NULL, &err);
+    if (!doc) return (int)err.code;
+    yyjson_doc_free(doc);
+    return 0;
+}
+
+// Full wrappers exported with stable names for Rust FFI
+void *nyjson_parse_doc(const char *text, size_t len, int *out_err_code) {
+    yyjson_read_err err;
+    yyjson_doc *doc = yyjson_read_opts(text, len, 0, NULL, &err);
+    if (!doc) {
+        if (out_err_code) *out_err_code = (int)err.code;
+        return NULL;
+    }
+    if (out_err_code) *out_err_code = 0;
+    return (void *)doc;
+}
+void nyjson_doc_free(void *doc) {
+    if (doc) yyjson_doc_free((yyjson_doc *)doc);
+}
+void *nyjson_doc_root(void *doc) {
+    if (!doc) return NULL;
+    return (void *)yyjson_doc_get_root((yyjson_doc *)doc);
+}
+
+int nyjson_is_null(void *v)  { return v && yyjson_is_null((yyjson_val *)v); }
+int nyjson_is_bool(void *v)  { return v && yyjson_is_bool((yyjson_val *)v); }
+int nyjson_is_int(void *v)   { return v && yyjson_is_sint((yyjson_val *)v); }
+int nyjson_is_real(void *v)  { return v && yyjson_is_real((yyjson_val *)v); }
+int nyjson_is_str(void *v)   { return v && yyjson_is_str((yyjson_val *)v); }
+int nyjson_is_arr(void *v)   { return v && yyjson_is_arr((yyjson_val *)v); }
+int nyjson_is_obj(void *v)   { return v && yyjson_is_obj((yyjson_val *)v); }
+
+int nyjson_get_bool_val(void *v) {
+    if (!v || !yyjson_is_bool((yyjson_val *)v)) return 0;
+    return yyjson_get_bool((yyjson_val *)v);
+}
+long long nyjson_get_sint_val(void *v) {
+    if (!v || !yyjson_is_sint((yyjson_val *)v)) return 0;
+    return (long long)yyjson_get_sint((yyjson_val *)v);
+}
+const char *nyjson_get_str_val(void *v) {
+    if (!v || !yyjson_is_str((yyjson_val *)v)) return NULL;
+    return yyjson_get_str((yyjson_val *)v);
+}
+
+size_t nyjson_arr_size_val(void *v) {
+    if (!v || !yyjson_is_arr((yyjson_val *)v)) return 0;
+    return yyjson_arr_size((yyjson_val *)v);
+}
+void *nyjson_arr_get_val(void *v, size_t idx) {
+    if (!v || !yyjson_is_arr((yyjson_val *)v)) return NULL;
+    return (void *)yyjson_arr_get((yyjson_val *)v, idx);
+}
+
+size_t nyjson_obj_size_val(void *v) {
+    if (!v || !yyjson_is_obj((yyjson_val *)v)) return 0;
+    return yyjson_obj_size((yyjson_val *)v);
+}
+void *nyjson_obj_get_key(void *v, const char *key) {
+    if (!v || !yyjson_is_obj((yyjson_val *)v) || !key) return NULL;
+    return (void *)yyjson_obj_get((yyjson_val *)v, key);
+}