✨ feat: 灵台引擎五神齐备与 Go/Rust 官方绑定（WP-15）

- C++ 新增四模块（modules.cpp，19 个导出符号全部 hj_*）：
  小周天 hj_stream：流会话（sequence/delta_index 单调）与 content.block.delta envelope 确定性编码（重放字节一致）
  烛照 hj_policy：URL 协议白名单（拒 file/javascript/data）、路径授权根与 .. 段拒绝、幂等键非空≤128、四维决策表（autonomy×risk→allow/ask/deny，非法输入 deny fail-closed）
  洛书 hj_plan：预算核算（达限/负数拒绝）
  河图 hj_recall：确定性重排（词频×稳定排序，canonical JSON 输出；非法输入 PARSE_FAILED）
- doctest 22 用例 20135 断言全绿（含每模块 golden 与确定性双跑）
- Go 绑定（cgo 自包含编译引擎源码）：Engine RAII/TransformMarkdown/ValidateURL/ValidatePath/Decide/CheckBudget/RecallRerank；go test 3 用例通过（transform/rerank golden 与 C++ 字节一致）
- Rust 绑定（bindgen 生成 + 安全包装）：Engine RAII（Drop 释放）、Error 枚举映射全部 HjStatus、Send/Sync（HjEngine 线程安全）；cargo test 3 用例通过（同 golden）
- 三端（C++/Go/Rust）与 Python golden 一致：同一 markdown 输入在四端输出字节相同（跨端一致性首次全语言验证）

engine/tests/test_modules.cpp

@@ -0,0 +1,106 @@
+// 小周天/烛照/洛书/河图模块测试。
+#include <cstring>
+#include <string>
+
+#include <doctest/doctest.h>
+
+#include "hunjing/lingtai.h"
+
+namespace {
+
+struct Engine {
+  HjEngine *ptr = nullptr;
+  Engine() { REQUIRE(hj_engine_new(HJ_ABI_VERSION, &ptr) == HJ_OK); }
+  ~Engine() { hj_engine_free(ptr); }
+};
+
+std::string buffer_text(HjBuffer *buf) {
+  std::string out(static_cast<const char *>(hj_buffer_data(buf)), hj_buffer_len(buf));
+  hj_buffer_free(buf);
+  return out;
+}
+
+}  // namespace
+
+TEST_CASE("小周天：delta envelope 确定性编码与序号单调") {
+  Engine e;
+  HjStream *stream = nullptr;
+  REQUIRE(hj_stream_new(e.ptr, &stream) == HJ_OK);
+  HjBuffer *b1 = nullptr;
+  REQUIRE(hj_stream_append_delta(stream, "block_01", "你", 3, &b1) == HJ_OK);
+  const std::string first = buffer_text(b1);
+  CHECK(first.find("\"type\":\"content.block.delta\"") != std::string::npos);
+  CHECK(first.find("\"sequence\":0") != std::string::npos);
+  CHECK(first.find("\"delta_index\":0") != std::string::npos);
+  HjBuffer *b2 = nullptr;
+  REQUIRE(hj_stream_append_delta(stream, "block_01", "好", 3, &b2) == HJ_OK);
+  const std::string second = buffer_text(b2);
+  CHECK(second.find("\"sequence\":1") != std::string::npos);
+  CHECK(second.find("\"delta_index\":1") != std::string::npos);
+  CHECK(hj_stream_sequence(stream) == 2);
+  // 确定性：同参数重放字节一致（重建会话）
+  HjStream *replay = nullptr;
+  REQUIRE(hj_stream_new(e.ptr, &replay) == HJ_OK);
+  HjBuffer *r1 = nullptr;
+  REQUIRE(hj_stream_append_delta(replay, "block_01", "你", 3, &r1) == HJ_OK);
+  CHECK(buffer_text(r1) == first);
+  hj_stream_free(replay);
+  hj_stream_free(stream);
+}
+
+TEST_CASE("烛照：URL 协议白名单") {
+  CHECK(hj_policy_validate_url("https://example.com/a") == HJ_OK);
+  CHECK(hj_policy_validate_url("http://example.com") == HJ_OK);
+  CHECK(hj_policy_validate_url("file:///etc/passwd") == HJ_ERR_POLICY_DENIED);
+  CHECK(hj_policy_validate_url("javascript:alert(1)") == HJ_ERR_POLICY_DENIED);
+  CHECK(hj_policy_validate_url("data:text/html,xx") == HJ_ERR_POLICY_DENIED);
+  CHECK(hj_policy_validate_url("") == HJ_ERR_INVALID_ARGUMENT);
+}
+
+TEST_CASE("烛照：路径约束") {
+  CHECK(hj_policy_validate_path("/data/domain/a.txt", "/data/domain") == HJ_OK);
+  CHECK(hj_policy_validate_path("/data/domain/../escape", "/data/domain") == HJ_ERR_POLICY_DENIED);
+  CHECK(hj_policy_validate_path("/etc/passwd", "/data/domain") == HJ_ERR_POLICY_DENIED);
+  CHECK(hj_policy_validate_path("", "/data") == HJ_ERR_INVALID_ARGUMENT);
+}
+
+TEST_CASE("烛照：幂等键与决策表") {
+  CHECK(hj_policy_validate_idempotency_key("abc") == HJ_OK);
+  CHECK(hj_policy_validate_idempotency_key("") == HJ_ERR_INVALID_ARGUMENT);
+  std::string long_key(129, 'x');
+  CHECK(hj_policy_validate_idempotency_key(long_key.c_str()) == HJ_ERR_INVALID_ARGUMENT);
+  // 决策表：autonomy（0 自省/1 循律/2 请命/3 禁域）× risk（0 只读/1 副作用/2 高影响）
+  CHECK(hj_policy_decide(1, 0) == 0);  // 循律+只读 = allow
+  CHECK(hj_policy_decide(0, 0) == 0);  // 自省+只读 = allow
+  CHECK(hj_policy_decide(2, 0) == 1);  // 请命+只读 = ask
+  CHECK(hj_policy_decide(1, 1) == 1);  // 循律+副作用 = ask
+  CHECK(hj_policy_decide(1, 2) == 1);  // 循律+高影响 = ask
+  CHECK(hj_policy_decide(0, 2) == 2);  // 自省+高影响 = deny
+  CHECK(hj_policy_decide(3, 0) == 2);  // 禁域 = deny
+  CHECK(hj_policy_decide(9, 0) == 2);  // 非法输入 = deny（fail-closed）
+}
+
+TEST_CASE("洛书：预算核算") {
+  CHECK(hj_plan_check_budget(5, 10) == HJ_OK);
+  CHECK(hj_plan_check_budget(10, 10) == HJ_ERR_LIMIT_EXCEEDED);
+  CHECK(hj_plan_check_budget(-1, 10) == HJ_ERR_INVALID_ARGUMENT);
+}
+
+TEST_CASE("河图：确定性重排") {
+  const char *input =
+      "{\"query_terms\":[\"魂镜\",\"记忆\"],\"candidates\":["
+      "{\"id\":\"a\",\"text\":\"魂镜 记忆 系统\"},{\"id\":\"b\",\"text\":\"无关内容\"},"
+      "{\"id\":\"c\",\"text\":\"记忆 一条\"}]}";
+  HjBuffer *buf = nullptr;
+  REQUIRE(hj_recall_rerank(input, &buf) == HJ_OK);
+  const std::string out = buffer_text(buf);
+  CHECK(out.find("{\"id\":\"a\",\"score\":20}") != std::string::npos);
+  CHECK(out.find("{\"id\":\"c\",\"score\":10}") != std::string::npos);
+  CHECK(out.find("{\"id\":\"b\",\"score\":0}") != std::string::npos);
+  CHECK(out.find("\"a\"") < out.find("\"c\""));
+  HjBuffer *again = nullptr;
+  REQUIRE(hj_recall_rerank(input, &again) == HJ_OK);
+  CHECK(buffer_text(again) == out);
+  HjBuffer *bad = nullptr;
+  CHECK(hj_recall_rerank("not json", &bad) == HJ_ERR_PARSE_FAILED);
+}