feat(layout-review): address review findings on pages 7-12

Find Duplicates (01_deduplicator):
- Delete the redundant outer Options wrapper; surface threshold +
  survivor rule directly, push the rest behind a single Advanced pane.
- Disambiguate competing primaries: top result is an auto-resolved
  preview (secondary download), review decisions are the single primary.
- Plain-English match labels (exact / approximate); clarify the third.
- Lift the match-card caption to a one-time instruction; note delimiter
  is delimited-text-only.

Quality Check (08_validator_reporter) — stub:
- Remove the dead disabled "Load rules file (JSON)" uploader so the
  stub invites a single action; keep the informative feature list.

Map Columns (05_column_mapper):
- Regroup schema -> mapping -> strategy/advanced (core task contiguous).
- Make preset-vs-Advanced precedence legible (Custom + modified marker).
- Adopt the compact file-intake banner; drop the duplicate resolved-
  mapping table; fix the add-row gutter style.

Combine Files (07_multi_file_merger) — stub:
- Actually disable the Merge CTA (add the disabled attribute).

PDF to CSV (10_pdf_extractor):
- Drop page/raw from the default preview to match export + fix the
  horizontal clip; surface raw via per-row affordance + overflow-x.
- Move the column selector above the download button; give auto-excluded
  rows a reason; align the files card to Home; de-dupe the row count.

Automated Workflows (09_pipeline_runner):
- Replace hand-edited JSON step config with per-step control expanders;
  JSON moved behind Advanced import/export.
- Editing the table marks the mode modified; fold the empty error column
  into the status pill; render summaries as plain English; collapse the
  explainer by default.

Cross-cutting items (stub standardization on page 10, shared disabled-
field token, remaining intake rollout) deferred to a holistic pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

layout-review/07_multi_file_merger.html

@@ -72,7 +72,7 @@
 
       <hr class="dt-divider">
 
-      <button class="dt-btn dt-btn-primary dt-btn-block is-disabled">Merge Files</button>
+      <button class="dt-btn dt-btn-primary dt-btn-block is-disabled" disabled>Merge Files</button>
 
     </div>
   </main>