Remove dead and test-only code: row-reference oracle, old_docs, test-only demand model, batch bridge, memo snapshot

Code that production never reaches, found by a repo-wide audit and checked with git grep on main at cef05d20. None of it is tracked by #1010 or its sub-issues. Removing it cuts about 6,300 lines.

The stage column says which #1010 stage issue each item belongs to.

#	Remove	Evidence	Stage	Lines
1	Row-at-a-time reference operators: `executor/src/operators/row_reference/` (11 files), `operators/aggregate/row_reference.rs`, and the `row_reference::enabled_for` hook (`operators/mod.rs:437`)	`#[cfg(test)]`. Tests run each operator twice, once under `with_row_reference`, and compare the outputs (`harness::assert_matches_reference`).	#1016	~3,100
2	`old_docs/` (README plus `design.md` and the `l1`–`l4` docs)	No reference anywhere in the repo (code, docs, CI, tools). `docs/` replaces it.	–	~1,770
3	`plan-selection/src/search/costing/demand.rs` (`derive_candidate_demand`, `CandidateDemand`, `BoundaryConsumer`)	`#[cfg(test)]` (`costing/mod.rs:6`). Only its own tests call it, and they never compare it against the production cost evaluator.	#1015	~408
4	Duplicated corpus helpers in the devtools bins: `col`, `dqc_catalog`, `netflow_catalog`, `bgp_catalog`, `sql_stmts`/`sql_statements`, `promql_lines`/`corpus_lines`, `parse_sample_interval`	Each of `sketch_coverage.rs`, `variant_coverage.rs`, `analyze_corpora.rs` and `examples/canonical_examples.rs` keeps its own copy, and `bgp_catalog` already differs between copies. `sketch_coverage.rs:3` says it "mirrors `variant_coverage`'s corpus list exactly". Replace with one `corpora` module in the devtools lib, and consider merging `sketch_coverage` into `variant_coverage`.	#1008	~200–320
5	`executor/src/runtime/batch_execution.rs` (`evaluate_batch`, `evaluate_inputs`, `evaluate_source`, `evaluate_dag`)	`evaluate_inputs` has no callers. Every other function is reached only from tests; the one non-test-file use is a test module in `operators/aggregate/temporal.rs:405`. The module doc calls it a "bridge for deployments" that does not exist. Move what that test needs into the test.	#1016	~213
6	`logical-asap-optimization/src/pass2/memo/shared_producer_snapshot.rs`	`#[cfg(test)]` (`pass2/memo.rs:16`). An FNV hash of the whole memo, recorded to show the #959 refactor changed no candidates. Every unrelated memo change now has to re-record it (it already was once, for #1032). The rule tests in `pass2/memo/rules/` cover the behavior.	#1013	~188
7	`optimize_physical_asap_without_query_time_raw_scans`, `every_assignment_scans_raw_at_query_time`, and the private `reads_raw_at_query_time` (`physical-asap-optimization/src/lib.rs:455-547`)	No callers anywhere, including tests.	#1014	~93

Decisions needed

Item 1: confirm that columnar parity is accepted, and decide which outputs to keep as fixed expected-row tests per operator before deleting the oracle.
Item 6: delete the snapshot now, or keep it until the One shared-producer rule: cover every reader's need, derive each reader (top-k, summary size, panes, ranks, …) #954 / Reorganize by stage: one memo-based Pass 2, Stage 1 finishes the memo, deployment inputs split by stage, asap-planner as the only entry point #958 follow-ups land.

Done when

Each item is removed (item 4: deduplicated), and cargo test --workspace and CI pass.
No public API changes outside asap-physical-asap-optimization (item 7) and the devtools lib (item 4).

🤖 Generated with Claude Code

Additions from the per-crate review in #1054 (main at cef05d2). Each item was checked with a grep that excludes #[cfg(test)] modules, tests/ and *_tests.rs. I also searched ASAPQuery-backend and ASAPCollector origin/main.

No users anywhere (delete):

run_stage1_to_stage3_from_pass1 (plan-selection/src/search/pipeline.rs:218, re-exported at search/mod.rs:44).
asap_aware_cse::with_shared_candidates (logical-asap-optimization/src/pass2/asap_aware_cse.rs:521).
hydra_kind_for, default_hydra_params (types/src/ir/schema/sketch.rs:501, :529).
MeasuredCpu, MeasuredResources (types/src/workload/resources/; used only inside that module).

Public but used only by tests (move under #[cfg(test)] or a test-support feature):

logical:
- accuracy::native_target (accuracy/mod.rs:91)
- may_change_rollup_candidate (asap_aware_cse.rs:2048)
- pane_configurations, pane_width_divisors (memo/shared_configurations.rs)
- expand_concrete_summary_state_groups, _in_domain (memo/state_groups.rs:58, :67)
- local_pane_candidates, add_local_window_composition (memo/window_candidates.rs)
physical: physical_candidate_count (lib.rs:689), materializes_any.
plan-selection: confirmed_weights, with_confirmed_weights.
types:
- compile_physical_asap_dag, compile_physical_asap_workload
- validate_at_ingestion, planned_data_state
- default_cardinality, default_quantile