Crop ratios and selection start, Vignette on empty layers, text colour previews (12.10c); mutation runs use 12 cores

TASKS.md

@@ -377,7 +377,7 @@ The panel of 4.6 shows and edits what the session holds so far. Each item adds i
 - 12.9b round 2: PASS, no findings.
 - [x] 12.10a Versions 1.2.5–1.2.7, part one: the project format's version in one place (`4cc9951`); the layer context menu, routed by the list, with its layer actions and validation (`6fa115e`, `2f1e796`, `5c5f05b`, `1366f68`), without the Layer Effects entry (`5d7adba`). Codex review: 3 rounds, PASS.
 - [x] 12.10b Part two: copying and pasting whole layers within and between projects (`5ef5b0a`, `c873453`); duplicating every selected layer, stacked above the topmost, folders with Ctrl+J (`245db93`, `2f1537f`). Codex review: 3 rounds, the third's finding (a history manager re-setting the current entry) fixed and closed.
-- [ ] 12.10c Part three: crop ratios 3:4 and 9:16 (`8b5a6af`) and a crop that starts at the selection (`5ece82b`); Vignette round by default, an empty layer painted across the canvas (`0488cab`); text colour previews from the pickers (`3317d02`, `4e5f4ec`); the tab strip's steady edge fade (`1fb6a3f`) and the title bar's free space dragging the window (`e8ed83b`), each where the twin has its subject. `c4244c4` is reverted in `67301d2`; the format documents (`156c38c`, `4455a72`) are 12.13's.
+- [x] 12.10c Part three: crop ratios 3:4 and 9:16 (`8b5a6af`) and a crop that starts at the selection (`5ece82b`); Vignette round by default, an empty layer painted across the canvas (`0488cab`); text colour previews from the pickers (`3317d02`, `4e5f4ec`); the tab strip's steady edge fade (`1fb6a3f`) and the title bar's free space dragging the window (`e8ed83b`), each where the twin has its subject. `c4244c4` is reverted in `67301d2`; the format documents (`156c38c`, `4455a72`) are 12.13's. Codex review: 2 rounds, PASS. The tab strip's two commits have no subject here (no fade; the desktop's title bar drags).
 - [ ] 12.11 Versions 1.2.8–1.2.10: the document's own pixel budget, PSB, simple Photoshop text as editable text, background-only PSDs, oversized Photoshop layers cropped, clicked text starting on its first baseline, live text opened by a double click with the Move tool (`a5721b2`), marching ants at screen resolution, SVG import (Qt SVG).
 - [ ] 12.12 Version 1.2.11: masks painted anywhere on the canvas, moved unlinked masks under effects, effects kept on screen while text is edited, masks painted and steps undone (`b683acb`), mask thumbnails' ground, text shown as its committed pixels, numeric label scrubbing.
 - [ ] 12.13 Version 1.3: reloading a project changed on disk (`ed5ddea`, merged in 1.3), its manifest-and-sizes fingerprint (`cd4061a`), editing while a project saves, images decoded from memory, the guide for AI agents writing projects.