feat: support Paimon scalar index scans

Bundle the Paimon global index components so predicate planning can load
BTree index factories and prune candidate splits for indexed tables.

Add a fixture with overlapping candidate ranges to exercise matching,
range, projection, and empty index probes through the existing scan
path.

Keep bundled dependency builds from pulling in unrelated test targets
during the extension build.

Co-authored-by: GPT-5.5 <codex@users.noreply.github.com>

Author: mrdrivingduck

CMakeLists.txt

@@ -38,7 +38,8 @@ file(MAKE_DIRECTORY ${PAIMON_CPP_INCLUDE})
 set(PAIMON_CPP_PATCHES
   ${CMAKE_CURRENT_SOURCE_DIR}/patches/paimon-cpp-install-arrow-headers.patch
   ${CMAKE_CURRENT_SOURCE_DIR}/patches/paimon-cpp-macos-ndebug-for-checked-cast.patch
-  ${CMAKE_CURRENT_SOURCE_DIR}/patches/paimon-cpp-disable-global-constructors-warning.patch)
+  ${CMAKE_CURRENT_SOURCE_DIR}/patches/paimon-cpp-disable-global-constructors-warning.patch
+  ${CMAKE_CURRENT_SOURCE_DIR}/patches/paimon-cpp-disable-re2-tests.patch)
 
 # Build patch command: apply each patch idempotently
 set(PAIMON_CPP_PATCH_SCRIPT "")
@@ -68,6 +69,8 @@ ExternalProject_Add(paimon_cpp_ep
     -DPAIMON_ENABLE_LUCENE=OFF
   BUILD_BYPRODUCTS
     ${PAIMON_CPP_LIB}/libpaimon${CMAKE_SHARED_LIBRARY_SUFFIX}
+    ${PAIMON_CPP_LIB}/libpaimon_file_index${CMAKE_SHARED_LIBRARY_SUFFIX}
+    ${PAIMON_CPP_LIB}/libpaimon_global_index${CMAKE_SHARED_LIBRARY_SUFFIX}
     ${PAIMON_CPP_LIB}/libpaimon_local_file_system${CMAKE_SHARED_LIBRARY_SUFFIX}
     ${PAIMON_CPP_LIB}/libpaimon_jindo_file_system${CMAKE_SHARED_LIBRARY_SUFFIX}
     ${PAIMON_CPP_LIB}/${JINDOSDK_C_INSTALLED_NAME}
@@ -120,6 +123,8 @@ add_dependencies(${TARGET_NAME}_loadable_extension paimon_cpp_ep)
 set(PAIMON_CPP_LIBS
   ${PAIMON_CPP_LIB}/libpaimon${CMAKE_SHARED_LIBRARY_SUFFIX}
   $<$<NOT:$<PLATFORM_ID:Darwin>>:-Wl,--no-as-needed>
+  ${PAIMON_CPP_LIB}/libpaimon_file_index${CMAKE_SHARED_LIBRARY_SUFFIX}
+  ${PAIMON_CPP_LIB}/libpaimon_global_index${CMAKE_SHARED_LIBRARY_SUFFIX}
   ${PAIMON_CPP_LIB}/libpaimon_local_file_system${CMAKE_SHARED_LIBRARY_SUFFIX}
   ${PAIMON_CPP_LIB}/libpaimon_jindo_file_system${CMAKE_SHARED_LIBRARY_SUFFIX}
   ${PAIMON_CPP_LIB}/${JINDOSDK_C_INSTALLED_NAME}
@@ -143,6 +148,8 @@ endif()
 # Bundle paimon-cpp runtime dependencies next to paimon.duckdb_extension.
 set(PAIMON_CPP_RUNTIME_BUNDLE_LIBS
   ${PAIMON_CPP_LIB}/libpaimon${CMAKE_SHARED_LIBRARY_SUFFIX}
+  ${PAIMON_CPP_LIB}/libpaimon_file_index${CMAKE_SHARED_LIBRARY_SUFFIX}
+  ${PAIMON_CPP_LIB}/libpaimon_global_index${CMAKE_SHARED_LIBRARY_SUFFIX}
   ${PAIMON_CPP_LIB}/libpaimon_local_file_system${CMAKE_SHARED_LIBRARY_SUFFIX}
   ${PAIMON_CPP_LIB}/libpaimon_jindo_file_system${CMAKE_SHARED_LIBRARY_SUFFIX}
   ${PAIMON_CPP_LIB}/${JINDOSDK_C_RUNTIME_NAME}