Create biergarten brewery pipeline project (#199)

pipeline/includes/data_generation/llama_generator_helpers.h

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+#ifndef BIERGARTEN_PIPELINE_INCLUDES_DATA_GENERATION_LLAMA_GENERATOR_HELPERS_H_
+#define BIERGARTEN_PIPELINE_INCLUDES_DATA_GENERATION_LLAMA_GENERATOR_HELPERS_H_
+
+/**
+ * @file data_generation/llama_generator_helpers.h
+ * @brief Shared helper APIs used by LlamaGenerator translation units.
+ */
+
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+#include <string>
+#include <string_view>
+
+#include "data_model/brewery_result.h"
+
+struct llama_vocab;
+using llama_token = int32_t;
+
+/**
+ * @brief Normalizes and truncates regional context.
+ *
+ * @param region_context Input regional context text.
+ * @param max_chars Maximum output length.
+ * @return Processed region context.
+ */
+std::string PrepareRegionContext(std::string_view region_context,
+                                 size_t max_chars = 2000);
+
+/**
+ * @brief Decodes a sampled token and appends it to output text.
+ *
+ * @param vocab Model vocabulary.
+ * @param token Sampled token id.
+ * @param output Output text buffer.
+ */
+void AppendTokenPiece(const llama_vocab* vocab, llama_token token,
+                      std::string& output);
+
+/**
+ * @brief Validates and parses brewery JSON output.
+ *
+ * @param raw Raw model output.
+ * @param brewery_out Parsed brewery payload.
+ * @return Validation error message if invalid, or std::nullopt on success.
+ */
+std::optional<std::string> ValidateBreweryJson(const std::string& raw,
+                                               BreweryResult& brewery_out);
+
+#endif  // BIERGARTEN_PIPELINE_INCLUDES_DATA_GENERATION_LLAMA_GENERATOR_HELPERS_H_