Add Lightroom's export and copy shortcuts to develop

Ctrl+E opens an export sheet: the export defaults on their own, over the
photograph, with an Export button. Ctrl+Shift+E exports straight away on
those defaults. There is no per-export copy of the settings, so what is
chosen in the sheet is saved as it is on the settings page, and the next
Ctrl+Shift+E uses it.

To make that one set of controls in two places, the export options move
out of the settings page into export.slint: an `ExportOptions` global
that Rust writes once, and two panels that read it. The window no longer
forwards forty `settings-*` properties to the page.

Ctrl+Shift+C opens a copy sheet with the edit-kind chips the preset
sheet already uses and a Copy button, which is how a paste leaves each
photograph's crop and rotation alone (Compose off). A and D step along
the roll beside the arrows. While either sheet is up the develop keys
stand down, so A cannot change the photograph behind the form, and
Escape closes it.

docs/gestures.md

@@ -5,7 +5,7 @@
 
 Every entry here is extracted from the comment beside the code that implements it, so this file cannot describe a gesture the application does not have. Add one by writing a `GESTURE:` block next to the implementation; there is nowhere else to write it.
 
-41 gestures, in 4 places.
+44 gestures, in 4 places.
 
 ## Develop
 
@@ -25,7 +25,7 @@ Sampling a neutral is the first move of the tonal pass — every colour judgemen
 
 Anchored on the fingers' midpoint, and on the pointer, so the gesture reads as magnifying the picture rather than sliding it about. Double-tap is the way to an exact 1:1; this is the way to everything in between.
 
-<sub>`ui/dr-ui/ui/app.slint:1782`</sub>
+<sub>`ui/dr-ui/ui/app.slint:1701`</sub>
 
 ### Move a magnified photograph about
 
@@ -34,7 +34,7 @@ Anchored on the fingers' midpoint, and on the pointer, so the gesture reads as m
 
 Only once there is something outside the viewport to reach, which is why the cursor becomes a hand exactly then. The view is clamped to the frame: panning past the edge would show undefined area beside the photograph, and that reads as a rendering fault rather than as the end of the picture.
 
-<sub>`ui/dr-ui/ui/app.slint:1873`</sub>
+<sub>`ui/dr-ui/ui/app.slint:1792`</sub>
 
 ### Paint a mask by hand
 
@@ -43,7 +43,7 @@ Only once there is something outside the viewport to reach, which is why the cur
 
 A model's mask stops inside a shoulder and leaks into the hair, and no single edge control fixes two errors that go opposite ways. The whole stroke is one step in the history, so taking a mark back costs one press however long it took to make.
 
-<sub>`ui/dr-ui/ui/app.slint:1960`</sub>
+<sub>`ui/dr-ui/ui/app.slint:1879`</sub>
 
 ### Take back the last change
 
@@ -53,7 +53,7 @@ A model's mask stops inside a shoulder and leaks into the hair, and no single ed
 
 A whole drag is one step, so undo takes back a decision rather than a frame of a gesture. The list is there because arriving six steps back costs what arriving from one does.
 
-<sub>`ui/dr-ui/ui/app.slint:2180`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2107`</sub>
 
 ### Do it again after taking it back
 
@@ -61,7 +61,7 @@ A whole drag is one step, so undo takes back a decision rather than a frame of a
 - **Pointer** — Click it, or press Redo in the History header
 - **Keyboard** — Ctrl+Shift+Z
 
-<sub>`ui/dr-ui/ui/app.slint:2193`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2120`</sub>
 
 ### Copy the settings from this photograph
 
@@ -71,7 +71,7 @@ A whole drag is one step, so undo takes back a decision rather than a frame of a
 
 The button is the copy that has to work: a tablet has no modifier key to hold and no menu bar to hang the action from. The shortcut is an accelerator for a control that is on screen either way.
 
-<sub>`ui/dr-ui/ui/app.slint:2226`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2153`</sub>
 
 ### Paste the settings onto this photograph
 
@@ -81,7 +81,37 @@ The button is the copy that has to work: a tablet has no modifier key to hold an
 
 The button names what would be pasted — "3 adjustments", and whether the crop is coming with it — which the shortcut cannot say. Both paste the same scope.
 
-<sub>`ui/dr-ui/ui/app.slint:2238`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2165`</sub>
+
+### Choose which kinds of edit a copy carries
+
+- **Touch** — Open Presets and toggle the kinds
+- **Pointer** — Open Presets and toggle the kinds
+- **Keyboard** — Ctrl+Shift+C, which offers Copy beside them
+
+Lightroom's Copy Settings. Pasting a look across a shoot usually means leaving each frame's crop and rotation alone, and that is a choice to make at the moment of copying.
+
+<sub>`ui/dr-ui/ui/app.slint:2182`</sub>
+
+### Export this photograph as the last one was
+
+- **Touch** — Press Export in the top bar
+- **Pointer** — Press Export in the top bar
+- **Keyboard** — Ctrl+Shift+E
+
+Every export runs on the defaults in Settings, so "as the last one was" is what the button already does. The chord is Lightroom's and darktable's, kept so hands that learned it there need not learn it again.
+
+<sub>`ui/dr-ui/ui/app.slint:2211`</sub>
+
+### Choose how to export, then export
+
+- **Touch** — Open Settings, then Export defaults
+- **Pointer** — Open Settings, then Export defaults
+- **Keyboard** — Ctrl+E
+
+The export sheet is the export defaults alone with an Export button. What is chosen there is kept, so it is also what the next Ctrl+Shift+E uses.
+
+<sub>`ui/dr-ui/ui/app.slint:2223`</sub>
 
 ### Change which group of adjustments is on screen
 
@@ -91,7 +121,7 @@ The button names what would be pasted — "3 adjustments", and whether the crop
 
 The groups are whatever the operation set declares itself to be about, so there are as many as the pipeline has and no key can be assigned to one of them by name. Stepping is the binding that survives a node being added.
 
-<sub>`ui/dr-ui/ui/app.slint:2265`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2248`</sub>
 
 ### Look at the photograph at 1:1
 
@@ -101,17 +131,17 @@ The groups are whatever the operation set declares itself to be about, so there
 
 Noise reduction and capture sharpening are judgements about single pixels, and a fitted view averages several of the file's into each one on screen — so the frame looks softer than it is and the correction goes too far. The point and the magnification survive opening the next photograph, which is what makes checking the same eye across forty portraits forty keystrokes rather than forty pans.
 
-<sub>`ui/dr-ui/ui/app.slint:2300`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2283`</sub>
 
 ### Move to the next or previous photograph
 
 - **Touch** — Tap a frame in the roll along the foot of the canvas
 - **Pointer** — Click a frame in the roll
-- **Keyboard** — Right arrow or space for the next, left arrow for the one before
+- **Keyboard** — Right arrow, D or space for the next; left arrow or A for the one before
 
-The edit on screen is saved on the way out, so stepping through a folder is as much a departure as going back to the grid and loses nothing.
+The edit on screen is saved on the way out, so stepping through a folder is as much a departure as going back to the grid and loses nothing. A and D as well as the arrows, so the left hand steps along the roll while the right stays on the mouse. Unmodified only: Ctrl+D and Ctrl+A are not this.
 
-<sub>`ui/dr-ui/ui/app.slint:2352`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2335`</sub>
 
 ### See the photograph before you edited it
 
@@ -121,7 +151,7 @@ The edit on screen is saved on the way out, so stepping through a folder is as m
 
 Held rather than toggled, and no split screen: a split halves the working image on the tablet the column was sized for, and the comparison photographers describe making is a flick back and forth. It takes no history step, so checking whether a frame is overcooked costs nothing to undo afterwards.
 
-<sub>`ui/dr-ui/ui/app.slint:2476`</sub>
+<sub>`ui/dr-ui/ui/app.slint:2468`</sub>
 
 ### Put one control back to its default