RAGFlow go API server (#13240)

# RAGFlow Go Implementation Plan 🚀

This repository tracks the progress of porting RAGFlow to Go. We'll
implement core features and provide performance comparisons between
Python and Go versions.

## Implementation Checklist

- [x] User Management APIs
- [x] Dataset Management Operations
- [x] Retrieval Test
- [x] Chat Management Operations
- [x] Infinity Go SDK

---------

Signed-off-by: Jin Hai <haijin.chn@gmail.com>
Co-authored-by: Yingfeng Zhang <yingfeng.zhang@gmail.com>

internal/cpp/term.h

@@ -0,0 +1,72 @@
+//
+// Created by infiniflow on 1/31/26.
+//
+
+#pragma once
+
+#include <string>
+#include <cstdint>
+#include <deque>
+
+class Term {
+public:
+    Term() : word_offset_(0), end_offset_(0), payload_(0) {
+    }
+
+    Term(const std::string &str) : text_(str), word_offset_(0), end_offset_(0), payload_(0) {
+    }
+
+    ~Term() {
+    }
+
+    void Reset();
+
+    uint32_t Length() { return text_.length(); }
+
+    std::string Text() const { return text_; }
+
+public:
+    std::string text_;
+    uint32_t word_offset_;
+    uint32_t end_offset_;
+    uint16_t payload_;
+};
+
+class TermList : public std::deque<Term> {
+public:
+    void Add(const char *text, const uint32_t len, const uint32_t offset, const uint32_t end_offset,
+             const uint16_t payload = 0) {
+        push_back(global_temporary_);
+        back().text_.assign(text, len);
+        back().word_offset_ = offset;
+        back().end_offset_ = end_offset;
+        back().payload_ = payload;
+    }
+
+    // void Add(cppjieba::Word &cut_word) {
+    //     push_back(global_temporary_);
+    //     std::swap(back().text_, cut_word.word);
+    //     back().word_offset_ = cut_word.offset;
+    // }
+
+    void Add(const std::string &token, const uint32_t offset, const uint32_t end_offset, const uint16_t payload = 0) {
+        push_back(global_temporary_);
+        back().text_ = token;
+        back().word_offset_ = offset;
+        back().end_offset_ = end_offset;
+        back().payload_ = payload;
+    }
+
+    void Add(std::string &token, const uint32_t offset, const uint32_t end_offset, const uint16_t payload = 0) {
+        push_back(global_temporary_);
+        std::swap(back().text_, token);
+        back().word_offset_ = offset;
+        back().end_offset_ = end_offset;
+        back().payload_ = payload;
+    }
+
+private:
+    static Term global_temporary_;
+};
+
+extern std::string PLACE_HOLDER;