When no margin detected, reserve a bit more space for comments

docs/final_output.md

@@ -4,6 +4,40 @@ This documents the current implementation, as of 2026-09-12. The return folder
 referred to as « À rendre » is named **`A Rendre`** on disk. JPEG files use the
 extension **`.jpg`**, not `.jpeg`.
 
+## Left space for Gemini comments
+
+`config.py` (or the file selected by `COPIENATOR_CONFIG`) can override:
+
+```python
+ANNOTATION_MARGIN_LEFT = 300
+ANNOTATION_LOW_MARGIN_LEFT = 400
+```
+
+These are added pixels at the 200 dpi annotation rendering scale. An answer
+uses the larger margin if any of its source fragments has a measured left
+margin below 20 mm (half the standard 40 mm). Unknown or insufficiently written
+pages retain the normal spacing. The 600 px comment width is unchanged, so
+comments can still overlap handwriting on pages with very little whitespace.
+
+Automatic `crop-labels` saves per-page measurements in the Cutleft schema.
+`split-answers` records source pages, crop rectangles and remaining margins in
+`*.layout.json` files beside answer PDFs. Those files follow copies, manual
+merges and vertical cuts. PDF fingerprints prevent using stale measurements
+after files are replaced. Legacy schemas and manual/full-page Cutleft runs
+without measurements keep the normal spacing.
+
+For an existing evaluation, rerun automatic `crop-labels`, `split-answers`, and
+annotation generation with overwrite to populate and use this metadata. Do
+this before handwritten review: existing Bnot/BGnot/BRnot annotation batches
+save their rendering geometry and reuse it when read back, even after settings
+change. Older batches without saved geometry keep their original 300 px offset.
+Do not overwrite a batch that still contains handwritten corrections to import.
+
+All fragments of one answer share one left offset. BGnot pads narrower answer
+images with white without resizing handwriting; fitting the wider document to
+screen or paper may reduce the displayed scale, and return-PDF page breaks can
+change. The extra space is also used by Anot and Bnot.
+
 ## Files and their sources
 
 After grouped correction and review: