The merge job and its page: a selection to a panorama DNG, confirmed first

dr_ui::merge is the orchestration with no interface in it: decode each
frame to sensor data and build its graph as a session would (orientation,
lens profile); render each through the camera-space tap at proxy size and
detect keypoints there, so the alignment is measured in the undistorted
frame the tiles are rendered in; align; solve one gain per frame from the
proxies' overlaps; draw the aligned set in colour for the page; then wait.
Nothing is written until a Decision arrives (FR-MRG-1). The merge writes
a linear DNG through the outbox with a destination record, so the drain
puts it beside its sources on a folder library and a server alike, and
the library rescans (FR-MRG-3).

merge.slint is the page, on the import page's model: the alignment
table with a failed frame named on its row and the button held off
(FR-MRG-5), the preview, the projection choice, Stop and Back. A
"Merge to panorama" button joins the grid's selection bar at two frames.

Headless, the example produces the fixture's 22 993 x 5 980 DNG in 45 s
on the reference desktop, exposures balanced across the stop of drift.

ui/dr-ui/Cargo.toml

@@ -33,6 +33,9 @@ dr-xmp.workspace = true
 dr-sync-folder.workspace = true
 dr-sync-nextcloud.workspace = true
 dr-export.workspace = true
+# The panorama's geometry and its keypoint detector (§3.11). The detector's
+# runtime is the same tract the faces and masks already carry.
+dr-pano = { workspace = true, features = ["xfeat", "embedded-model"] }
 dr-ingest.workspace = true
 dr-film.workspace = true
 # The lens profile database, here for the same reason dr-film is: dr-pipeline