…, rebuild_bench

Remove V1 NDJSON loader and supporting infrastructure (~4,200 lines):
- src/sync/slot_arena.rs (1016 lines) — V1 memory-mapped slot arena
- src/sync/progress.rs (113 lines) — V1 progress server
- src/sync/loader.rs (1847 lines) — V1 NDJSON loader
- src/sync/copy_queries.rs (364 lines) — V1 hardcoded COPY queries
- src/bin/rebuild_bench.rs (906 lines) — stale benchmark binary

Also removed:
- POST /load handler and LoadRequest struct from server.rs
- V1 download path (download_all_tables/download_table/download_single_table) from bulk_loader.rs
- ImageScalars, ResourceEnrichment, BulkLoadStats, finalize_from_bitmaps, scalars_to_json,
  cleanup_orphan_bitmaps and their tests from bulk_loader.rs
- AccumSink and its test from ingester.rs (depended on deleted BitmapAccum)
- V1 fallback in pg_sync.rs bin replaced with exit(1) + clear error

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- concurrent_engine: remove persist_dirty_dictionaries (no-op), compact_docstore,
  docstore_schema_version, indexed_field_names (all zero callers)
- sort: remove layer_bases, layer_bases_fused (zero callers);
  move slots_in_range behind #[cfg(test)]
- executor: remove with_string_maps, with_case_sensitive_fields, with_dictionaries,
  with_bitmap_silo, slot_matches_filters (all zero callers outside this file)
- filter: remove FilterField::distinct_count (zero callers)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

queries.rs: delete all V1 row structs (ImageRow, TagRow, ToolRow, TechniqueRow,
ResourceRow, OutboxRow, MetricRow, CollectionItemRow, StreamTagRow,
StreamResourceRow, StreamCollectionRow) and all dead fetch/range functions.
Keep: run_setup, run_setup_v2, get_max_ops_id, get_max_outbox_id,
upsert_cursor, SETUP_SQL, SETUP_V2_SQL, find_trigger_table, check_triggers_exist.

dump_processor.rs: delete ParsedRow::to_csv_row() — zero callers.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Deleted the HashMap-based eval() path from dump_expression.rs
(EvalContext, build_column_index, Expr::eval, FilterExpression::eval,
ComputedFieldDef::eval, ExprValue::as_str_value) and the corresponding
HashMap-based enrichment wrappers from dump_enrichment.rs
(LookupRow::get/to_csv_row/iter_columns, EnrichmentTable::get/child/
enrich/enrich_indexed, EnrichmentManager::enrich_row/enrich_row_indexed/
clear/drop_table/total_memory, resolve_dictionary_value,
resolve_expr_to_bitmap_key, DictionarySet). The indexed paths
(eval_indexed, enrich_indexed_into_with_buf, enrich_row_indexed_into)
are the only live production paths at 107M+ scale.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Deleted document_to_ops() (WAL refactor stub with zero external callers),
field_value_to_json() (only called by document_to_ops), qvalue_to_json()
(private helper for field_value_to_json), extract_multi_ints() (private
helper for document_to_ops), and OpsProcessorConfig struct (unused config
struct). Removed associated tests and cleaned up unused Duration/PathBuf
imports.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…nd #[cfg(test)]

These items have zero production callers — only used in test harnesses in
mutation.rs, executor.rs, and planner.rs tests. Gating them with
#[cfg(test)] removes them from release builds without deleting the tests
that rely on them.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Deleted handle_patch_documents, handle_filter_sync, FilterSyncRequest,
and FilterSyncEntry from server.rs — all returned 501 NOT_IMPLEMENTED
with no path to implementation. Removed their route registrations from
the router. Client code should use PUT upsert for all document writes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

The [[bench]] entry referenced a file that was never committed.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>