feat(pg): add Go-style large export APIs (streaming, COPY, snapshots)

Author: g2px1

CMakeLists.txt

@@ -119,6 +119,10 @@ if (UPQ_BUILD_EXAMPLES)
         target_link_libraries(upq_example_timeout PRIVATE upq)
         target_compile_definitions(upq_example_timeout PRIVATE DEV_STAGE=${DEV_STAGE})
 
+        add_executable(upq_example_large_exports examples/large_exports.cpp)
+        target_link_libraries(upq_example_large_exports PRIVATE upq)
+        target_compile_definitions(upq_example_large_exports PRIVATE DEV_STAGE=${DEV_STAGE})
+
         FetchContent_Declare(
                 ulog
                 GIT_REPOSITORY https://github.com/Usub-Foundation/ulog.git

README.md

@@ -19,8 +19,12 @@ with [ureflect](https://github.com/Usub-development/ureflect).
 * Safe transactional RAII wrapper (`PgTransaction`)
 * Parameter binding with `$1, $2, …`
 * Zero-copy non-blocking I/O pipeline
-* **NEW:** Reflection-aware queries (`query_reflect`, `exec_reflect`, `query_reflect_one`)  
+* **Reflection-aware queries** (`query_reflect`, `exec_reflect`, `query_reflect_one`)  
   → automatic struct ↔ SQL row mapping via `ureflect`
+* Large-export API — cursor-backed `PgRowStream`,
+  streaming `COPY TO` / `COPY FROM` with async sinks/sources,
+  `pg_export_snapshot` support for parallel consistent dumps
+  ([see docs](docs/large-exports.md))
 
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