Add critical result curation metadata

docs/critical_tables_db_model.md

@@ -102,11 +102,23 @@ One record per lookup cell:
 
 This stores:
 
+- `is_curated`
 - `raw_cell_text`
 - `description_text`
 - `raw_affix_text`
 - `parsed_json`
-- parse status / source metadata
+- `parse_status`
+- `source_page_number`
+- `source_image_path`
+- `source_image_crop`
+
+`is_curated` is an explicit workflow flag. Once a result is curated in the web editor, later importer runs must preserve curator-owned content instead of replacing the row wholesale.
+
+The source-image fields keep importer provenance separate from the editor snapshot stored in `parsed_json`:
+
+- `source_page_number` points to the rendered PDF page used for review
+- `source_image_path` stores the importer-managed relative PNG path for the cell crop
+- `source_image_crop` stores the crop geometry that produced the PNG and can be used for debugging alignment problems
 
 ### 6. `critical_branch`
 
@@ -284,6 +296,7 @@ Current curation flow:
    - base raw cell text
    - curated prose / description
    - raw affix text
+   - curated state
    - parse status
    - parsed JSON
    - nested `critical_branch` rows
@@ -293,6 +306,7 @@ Current curation flow:
 The corresponding API endpoints are:
 
 - `GET /api/tables/critical/{slug}/cells/{resultId}`
+- `GET /api/tables/critical/{slug}/cells/{resultId}/source-image`
 - `PUT /api/tables/critical/{slug}/cells/{resultId}`
 
-The save operation replaces the stored branches and effects for that cell with the submitted payload. That keeps manual edits deterministic and avoids trying to reconcile partial child-row diffs against importer-generated data.
+The save operation replaces the stored branches and effects for that cell with the submitted payload and updates the explicit curated flag. Importer-managed source provenance can still be refreshed on later imports without overwriting curated content.