chore: auto-commit (12 archivos)

- playground/tables/CMakeLists.txt
- playground/tables/data_table.cpp
- playground/tables/data_table_logic.cpp
- playground/tables/data_table_logic.h
- playground/tables/self_test.cpp
- playground/tables/tql.cpp
- playground/tables/viz.cpp
- playground/tables/viz.h
- playground/tables/llm_anthropic.cpp
- playground/tables/llm_anthropic.h
- ...

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

playground/tables/tql_to_sql.h

@@ -0,0 +1,41 @@
+// tql_to_sql: emite SQL DuckDB equivalente a una pipeline TQL State.
+// Pure. Sin DuckDB linkado. Solo string emit + validacion.
+// Ver issue 0080 + docs/TQL.md (seccion "SQL transpile subset").
+#pragma once
+
+#include "data_table_logic.h"
+#include <string>
+#include <vector>
+
+namespace tql_to_sql {
+
+struct SqlEmit {
+    std::string                 sql;       // SELECT/CTE chain DuckDB
+    std::vector<std::string>    params;    // bound values posicionales (?)
+    std::vector<std::string>    warnings;  // soft issues (col not found, etc.)
+    std::string                 error;     // si non-empty, emit fallo
+};
+
+// Pure: emite SQL DuckDB equivalente a stages 0..active del state.
+// `tables` provee schema (headers/types/name) de cada TableInput. El caller
+// es responsable de hidratar las tablas en DuckDB con esos nombres.
+// `up_to_stage = -1` => state.active_stage.
+SqlEmit emit_sql(const data_table::State& state,
+                  const std::vector<data_table::TableInput>& tables,
+                  int up_to_stage = -1);
+
+// Pure: valida que `formula` (cuerpo Lua de un derived col) este dentro del
+// subset SQL-transpilable. Si valido, retorna true. Si no, false + razon
+// concreta en `error_out` (categoria + token problematico).
+// Ver docs/TQL.md#sql-transpile-subset.
+bool is_transpilable(const std::string& formula, std::string& error_out);
+
+// Pure: transpila formula Lua subset -> SQL expression. Si fuera de subset,
+// retorna "" y rellena `error_out`. Asume is_transpilable retornaria true.
+// `in_headers` necesario para resolver `[col]` refs y emitir identifier
+// SQL apropiado (quoted si tiene char especial).
+std::string transpile_expr(const std::string& formula,
+                            const std::vector<std::string>& in_headers,
+                            std::string& error_out);
+
+} // namespace tql_to_sql