exam-marker: exam_templates.extraction_meta jsonb (P3 audit gate + provenance)

Applied to dev .94 2026-07-03. {engine, slug, audit:{cover_total,detected_total,status,anomaly}, counts}.
Pending prod (.156) — gated.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

volumes/db/cc/75-exam-marker-region-meta.sql

@@ -0,0 +1,12 @@
+--==========================================================================================
+-- 75. exam_response_areas.meta — rich recognition payload from the extraction service (P2)
+--==========================================================================================
+-- The extraction service (docling-exam-spike analyse contract) returns richer per-region detail than
+-- the thin first-pass could: per-option OMR box geometry + fill (boxes[]), select_n ("tick 2 of 5"),
+-- n_options, the expected unit/quantity for single-line answers, and the data_table an MC question reads.
+-- These have no dedicated columns; keep them in a jsonb sidecar so the canvas can render tick boxes /
+-- units / MC option counts without a column per attribute. Nullable, defaults to {}.
+alter table public.exam_response_areas add column if not exists meta jsonb not null default '{}'::jsonb;
+
+comment on column public.exam_response_areas.meta is
+  'Extraction-service recognition detail: {n_lines, unit, quantity, n_boxes, n_options, select_n, box_form, boxes:[{x0,y0,x1,y1,fill}], table:{grid,n_cells}}. Rendered by the canvas; not authoritative for marking.';

volumes/db/cc/76-exam-marker-extraction-meta.sql

@@ -0,0 +1,11 @@
+--==========================================================================================
+-- 76. exam_templates.extraction_meta — trust signal + provenance from the extraction service (P3)
+--==========================================================================================
+-- Records, per template, how the recognition was produced and whether it reconciled: the audit
+-- cover-total gate (cover_total vs detected_total, status, anomaly), the engine + slug used, and
+-- region counts. Lets the setup UI show "extraction: cover 100 = detected 100 ✓" (or flag an under-read),
+-- and lets the digital-text view resolve the paper's replica by slug. Nullable, defaults to {}.
+alter table public.exam_templates add column if not exists extraction_meta jsonb not null default '{}'::jsonb;
+
+comment on column public.exam_templates.extraction_meta is
+  'Extraction-service provenance + trust gate: {engine, slug, audit:{cover_total,detected_total,status,anomaly}, counts}.';