Add cudf::memory_resources for separate temporary/output allocation control - #15

…d output allocations

This large-scale refactoring introduces the cudf::memory_resources class that enables
fine-grained control over memory allocation by separating temporary (intermediate)
allocations from output (returned) allocations.

Key changes:
- Add cudf::memory_resources class in utilities/memory_resource.hpp with:
  * Two-argument constructor for explicit output and temporary MRs
  * Single-argument constructor for backward API compatibility
  * get_output_mr() and get_temporary_mr() accessor methods
  * Implicit conversion from rmm::device_async_resource_ref

- Update 562 files across the codebase:
  * 197 public API headers converted to accept cudf::memory_resources
  * 365+ implementation files updated to use resources.get_temporary_mr()
  * All Thrust exec_policy calls now include memory resource parameter
  * All rmm::device_uvector and device_buffer allocations updated

- Add validation support:
  * LIBCUDF_ERROR_ON_CURRENT_DEVICE_RESOURCE_REF environment variable
  * Enables strict checking that resources are threaded through all code paths
  * Helpful error messages for debugging

- Create comprehensive test suite:
  * memory_resources_tests.cpp with 20+ test cases
  * memory_resources_validation_tests.cpp with 10+ validation tests
  * Tests cover constructors, separate pools, tracking, validation mode, edge cases

- Add extensive documentation:
  * Implementation plan and design decisions
  * Refactoring summary with patterns used
  * Detailed list of targeted fixes applied
  * Test documentation and debugging guide
  * Validation script for verifying completeness

Patterns updated throughout codebase:
- rmm::device_async_resource_ref mr → cudf::memory_resources resources
- cudf::get_current_device_resource_ref() → resources.get_temporary_mr()
- rmm::exec_policy(stream) → rmm::exec_policy(stream, resources.get_temporary_mr())
- Function calls: pass entire resources object, not just get_output_mr()

Maintains backward API compatibility through implicit conversion while enabling
new functionality to use separate memory pools for optimization and profiling.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

…urces-refactoring

# Conflicts:
#	cpp/src/binaryop/compiled/binary_ops.cu
#	cpp/src/copying/copy.cu
#	cpp/src/copying/purge_nonempty_nulls.cu
#	cpp/src/copying/sample.cu
#	cpp/src/copying/shift.cu
#	cpp/src/datetime/datetime_ops.cu
#	cpp/src/dictionary/detail/concatenate.cu
#	cpp/src/dictionary/detail/merge.cu
#	cpp/src/dictionary/remove_keys.cu
#	cpp/src/dictionary/search.cu
#	cpp/src/dictionary/set_keys.cu
#	cpp/src/filling/repeat.cu
#	cpp/src/filling/sequence.cu
#	cpp/src/groupby/hash/hash_compound_agg_finalizer.cu
#	cpp/src/groupby/sort/group_collect.cu
#	cpp/src/groupby/sort/group_correlation.cu
#	cpp/src/groupby/sort/group_count.cu
#	cpp/src/groupby/sort/group_count_scan.cu
#	cpp/src/groupby/sort/group_histogram.cu
#	cpp/src/groupby/sort/group_m2.cu
#	cpp/src/groupby/sort/group_merge_lists.cu
#	cpp/src/groupby/sort/group_nth_element.cu
#	cpp/src/groupby/sort/group_nunique.cu
#	cpp/src/groupby/sort/group_quantiles.cu
#	cpp/src/groupby/sort/group_rank_scan.cu
#	cpp/src/groupby/sort/group_replace_nulls.cu
#	cpp/src/groupby/sort/group_std.cu
#	cpp/src/groupby/sort/sort_helper.cu
#	cpp/src/hash/md5_hash.cu
#	cpp/src/hash/murmurhash3_x64_128.cu
#	cpp/src/hash/murmurhash3_x86_32.cu
#	cpp/src/hash/xxhash_32.cu
#	cpp/src/hash/xxhash_64.cu
#	cpp/src/interop/to_arrow_host.cu
#	cpp/src/io/avro/reader_impl.cu
#	cpp/src/io/comp/compression.cu
#	cpp/src/io/comp/nvcomp_adapter.cu
#	cpp/src/io/csv/csv_gpu.cu
#	cpp/src/io/csv/durations.cu
#	cpp/src/io/json/json_column.cu
#	cpp/src/io/json/json_tree.cu
#	cpp/src/io/json/nested_json_gpu.cu
#	cpp/src/io/json/read_json.cu
#	cpp/src/io/orc/writer_impl.cu
#	cpp/src/io/parquet/writer_impl.cu
#	cpp/src/io/text/multibyte_split.cu
#	cpp/src/io/utilities/data_casting.cu
#	cpp/src/join/filtered_join.cu
#	cpp/src/join/join_utils.cu
#	cpp/src/join/mixed_join_semi.cu
#	cpp/src/join/sort_merge_join.cu
#	cpp/src/labeling/label_bins.cu
#	cpp/src/lists/combine/concatenate_list_elements.cu
#	cpp/src/lists/combine/concatenate_rows.cu
#	cpp/src/lists/contains.cu
#	cpp/src/lists/copying/concatenate.cu
#	cpp/src/lists/copying/copying.cu
#	cpp/src/lists/count_elements.cu
#	cpp/src/lists/dremel.cu
#	cpp/src/lists/explode.cu
#	cpp/src/lists/extract.cu
#	cpp/src/lists/interleave_columns.cu
#	cpp/src/lists/reverse.cu
#	cpp/src/lists/segmented_sort.cu
#	cpp/src/lists/sequences.cu
#	cpp/src/lists/set_operations.cu
#	cpp/src/lists/stream_compaction/apply_boolean_mask.cu
#	cpp/src/lists/utilities.cu
#	cpp/src/merge/merge.cu
#	cpp/src/partitioning/partitioning.cu
#	cpp/src/partitioning/round_robin.cu
#	cpp/src/quantiles/quantile.cu
#	cpp/src/quantiles/tdigest/tdigest.cu
#	cpp/src/quantiles/tdigest/tdigest_aggregation.cu
#	cpp/src/reductions/all.cu
#	cpp/src/reductions/any.cu
#	cpp/src/reductions/max.cu
#	cpp/src/reductions/min.cu
#	cpp/src/reductions/minmax.cu
#	cpp/src/reductions/nth_element.cu
#	cpp/src/reductions/scan/ewm.cu
#	cpp/src/reductions/scan/rank_scan.cu
#	cpp/src/reductions/scan/scan_exclusive.cu
#	cpp/src/reductions/scan/scan_inclusive.cu
#	cpp/src/reductions/segmented/counts.cu
#	cpp/src/reductions/segmented/nunique.cu
#	cpp/src/replace/clamp.cu
#	cpp/src/replace/nans.cu
#	cpp/src/replace/nulls.cu
#	cpp/src/reshape/byte_cast.cu
#	cpp/src/reshape/interleave_columns.cu
#	cpp/src/rolling/detail/rolling_collect_list.cu
#	cpp/src/round/round.cu
#	cpp/src/search/contains_scalar.cu
#	cpp/src/search/search_ordered.cu
#	cpp/src/sort/is_sorted.cu
#	cpp/src/sort/rank.cu
#	cpp/src/sort/segmented_sort.cu
#	cpp/src/stream_compaction/distinct_count.cu
#	cpp/src/stream_compaction/distinct_helpers.cu
#	cpp/src/stream_compaction/stable_distinct.cu
#	cpp/src/stream_compaction/unique.cu
#	cpp/src/stream_compaction/unique_count.cu
#	cpp/src/stream_compaction/unique_count_column.cu
#	cpp/src/strings/attributes.cu
#	cpp/src/strings/capitalize.cu
#	cpp/src/strings/char_types/char_types.cu
#	cpp/src/strings/convert/convert_booleans.cu
#	cpp/src/strings/convert/convert_datetime.cu
#	cpp/src/strings/convert/convert_durations.cu
#	cpp/src/strings/convert/convert_fixed_point.cu
#	cpp/src/strings/convert/convert_floats.cu
#	cpp/src/strings/convert/convert_hex.cu
#	cpp/src/strings/convert/convert_integers.cu
#	cpp/src/strings/convert/convert_ipv4.cu
#	cpp/src/strings/convert/int_cast.cu
#	cpp/src/strings/copying/concatenate.cu
#	cpp/src/strings/copying/copying.cu
#	cpp/src/strings/copying/shift.cu
#	cpp/src/strings/like.cu
#	cpp/src/strings/repeat_strings.cu
#	cpp/src/strings/reverse.cu
#	cpp/src/strings/scan/scan_inclusive.cu
#	cpp/src/strings/search/find.cu
#	cpp/src/strings/search/find_multiple.cu
#	cpp/src/strings/slice.cu
#	cpp/src/strings/split/partition.cu
#	cpp/src/strings/split/split.cu
#	cpp/src/strings/split/split_re.cu
#	cpp/src/strings/strip.cu
#	cpp/src/strings/utilities.cu
#	cpp/src/strings/wrap.cu
#	cpp/src/structs/scan/scan_inclusive.cu
#	cpp/src/text/deduplicate.cu
#	cpp/src/text/detokenize.cu
#	cpp/src/text/jaccard.cu
#	cpp/src/text/minhash.cu
#	cpp/src/text/ngrams_tokenize.cu
#	cpp/src/text/normalize.cu
#	cpp/src/text/stemmer.cu
#	cpp/src/text/tokenize.cu
#	cpp/src/text/vocabulary_tokenize.cu
#	cpp/src/text/wordpiece_tokenize.cu
#	cpp/src/transform/mask_to_bools.cu
#	cpp/src/transform/one_hot_encode.cu
#	cpp/src/unary/cast_ops.cu
#	cpp/src/unary/math_ops.cu