Web source: render at canvas size 1920x1080 — full-bleed widgets no longer truncated to upper-left

TASKS.md

@@ -917,17 +917,16 @@ capturing the primary display (which causes the infinity mirror effect).
 8. ✅ Preview shows live web content (not just a blank rectangle)
 9. ☐ Handle navigation errors, invalid URIs, timeout gracefully
 
-**Rendering model (2026-08-28, stable viewport + content-bounds crop):**
-the page renders ONCE at the size the element was created at (snapshot in `Register`, never
-tracked) — dragging the box never reflows the page; scrollbars suppressed via
-`overflow:hidden` html/body injection (background-transparent only otherwise). After each
-navigation the manager queries the page's real content rect (`scrollWidth/scrollHeight` vs
-`innerWidth/innerHeight`) and **crops the capture to the actual content bounds, anchored at
-(0,0)** — widgets that don't fill their viewport no longer stretch dead space across the box.
-`Stretch="Fill"` maps the cropped frame edge-to-edge (box is covered; the fill/adornment rect
-snaps to it). Graceful-error handling (item 9) is a follow-up. Rejected for the record:
-fixed-viewport 1920×1080 + `Uniform` (letterbox), CSS margin/100% reset (enlarged gaps),
-viewport==box (page reflow → truncation/scrollbars).
+**Rendering model (2026-08-28, canvas-size viewport + content-bounds crop):**
+the page renders at the MASTER CANVAS size (1920×1080), stable, never tracked. Two earlier bugs
+are both dead: (a) box-sized viewports clip full-bleed widgets to their upper-left chunk
+("truncated to the upper-left corner regardless of scaling" — the image is desktop-line space),
+(b) dragging the box reflowed the page (truncation/scrollbars). Scrollbars suppressed via
+`overflow:hidden` html/body injection. After each navigation the manager queries the page's real
+content rect (`scrollWidth/scrollHeight` vs `innerWidth/innerHeight`) and **crops the capture to
+the actual content bounds, anchored at (0,0)**. `Stretch="Fill"` maps the frame flush under the
+box — selection/adornment box always bounds the widget, pinned to (0,0), for any widget geometry.
+Graceful-error handling (item 9) is a follow-up.
 
 **Properties panel (2026-08-28):** web URI ✓/✕ icon buttons are `IsTabStop="False"` so Tab flows
 X→Y→W→H→URI; the ✕ button now clears the URI textbox (was reverting to the pre-accept snapshot).