Come back from develop on the photograph you were editing

Leaving develop returned to where the *grid* was, which after a walk
along the photo roll can be a thousand rows from the frame you had just
finished. So the one photograph you were certainly interested in was the
one the grid came back without.

Two positions, and the rule is not to pick one of them. The grid seeks to
the remembered position, then reveals the keyboard cursor -- which is now
put on the open photograph, and which moves the viewport as little as
will bring its row into view. A frame inside the remembered screenful
moves nothing at all; one outside it scrolls exactly far enough. One
rule, both behaviours.

The cursor rather than the selection, deliberately: `place_cursor` also
rewrites the selection, and a set of forty photographs assembled in the
grid must survive having one of them opened.

`reveal()` now also runs on the grid's `init`, since `cursor-row` is
initialised rather than changed when the subtree is rebuilt and no
handler would otherwise fire. Both it and the roll's centring defer while
the element has no height yet -- `init` runs before layout, where a
height of zero makes every row look off screen -- and a latch brings the
first real height back to the cursor without letting every later resize
haul the viewport around.

The capture-time marker follows the same move, for the same reason:
`load_window` rebuilds the axis only when the scope, the filter or the
total has changed, and none of them has. It is the same library seen from
a different row.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/gestures.md

@@ -54,7 +54,7 @@ The right match confidence is a property of your library, not of the model. "Wha
 
 Touch has no ctrl, so without a mode there is no way to select a second photograph — the first tap would open it. The hold is the fast way in and the button is the one that can be found.
 
-<sub>`ui/dr-ui/ui/library.slint:1292`</sub>
+<sub>`ui/dr-ui/ui/library.slint:1218`</sub>
 
 ### Add or remove one photograph
 
@@ -63,7 +63,7 @@ Touch has no ctrl, so without a mode there is no way to select a second photogra
 
 While selecting, a tap never opens. That is the whole point of the mode: one meaning per gesture at a time. Press Done to get tap-to-open back.
 
-<sub>`ui/dr-ui/ui/library.slint:1301`</sub>
+<sub>`ui/dr-ui/ui/library.slint:1227`</sub>
 
 ### Leave selecting
 
@@ -71,7 +71,7 @@ While selecting, a tap never opens. That is the whole point of the mode: one mea
 - **Pointer** — Press Done in the header
 - **Keyboard** — Escape
 
-<sub>`ui/dr-ui/ui/library.slint:1309`</sub>
+<sub>`ui/dr-ui/ui/library.slint:1235`</sub>
 
 ### Pick a photograph up to drag it
 
@@ -80,7 +80,7 @@ While selecting, a tap never opens. That is the whole point of the mode: one mea
 
 A finger on a photograph might be starting a scroll, and for the first half-second the grid assumes it is. Holding says otherwise, and the ring is the grid saying it heard — from there the drag cannot be lost to a scroll. A mouse never waits: the cursor is precise enough that a sideways drag is unambiguous from the first pixel.
 
-<sub>`ui/dr-ui/ui/library.slint:1339`</sub>
+<sub>`ui/dr-ui/ui/library.slint:1265`</sub>
 
 ### Select a range
 
@@ -89,7 +89,7 @@ A finger on a photograph might be starting a scroll, and for the first half-seco
 
 This replaced a double tap, which had no visible state and could take forty photographs by accident. The run is resolved by the catalog rather than by what is on screen, so the grid can scroll between the two taps — the ranges that hurt on a tablet are longer than a screenful, which is exactly where a finger sweep runs out.
 
-<sub>`ui/dr-ui/ui/library.slint:1404`</sub>
+<sub>`ui/dr-ui/ui/library.slint:1330`</sub>
 
 ### Find photographs with two people in them
 
@@ -98,7 +98,7 @@ This replaced a double tap, which had no visible state and could take forty phot
 
 "Any of them" is a union and "all of them" is an intersection. The tray is where both terms and the choice between them live, because a filter belongs on the filter bar.
 
-<sub>`ui/dr-ui/ui/library.slint:2086`</sub>
+<sub>`ui/dr-ui/ui/library.slint:2012`</sub>
 
 ### Resize the thumbnails
 
@@ -107,7 +107,7 @@ This replaced a double tap, which had no visible state and could take forty phot
 
 There is no wheel on a tablet, so without the pinch the cell size could only be changed by a control a finger cannot reach.
 
-<sub>`ui/dr-ui/ui/library.slint:2739`</sub>
+<sub>`ui/dr-ui/ui/library.slint:2665`</sub>
 
 ### File photographs in a collection
 
@@ -116,7 +116,7 @@ There is no wheel on a tablet, so without the pinch the cell size could only be
 
 The selection is what the drag carries, which is why selecting several is worth the mode: forty photographs file in one gesture.
 
-<sub>`ui/dr-ui/ui/library.slint:2936`</sub>
+<sub>`ui/dr-ui/ui/library.slint:2862`</sub>
 
 ### Open a photograph
 
@@ -125,7 +125,7 @@ The selection is what the drag carries, which is why selecting several is worth
 
 A tap opens; a tap that *moved* does not. Travel is what separates a deliberate tap from a hand brushing past, and it is the only thing that does: the two are the same length. An earlier version required the finger to dwell 120 ms instead, and that rejected ordinary taps — a real tap is often quicker than a brush.
 
-<sub>`ui/dr-ui/ui/library.slint:3204`</sub>
+<sub>`ui/dr-ui/ui/library.slint:3130`</sub>
 
 ### Rate a photograph without opening it
 
@@ -135,7 +135,7 @@ A tap opens; a tap that *moved* does not. Travel is what separates a deliberate
 
 A star has to take the press without it also reaching the cell, or every rating throws the user into develop.
 
-<sub>`ui/dr-ui/ui/library.slint:3324`</sub>
+<sub>`ui/dr-ui/ui/library.slint:3250`</sub>
 
 ### Drop the selection but keep selecting
 
@@ -144,7 +144,7 @@ A star has to take the press without it also reaching the cell, or every rating
 
 Distinct from Done, which leaves the mode entirely. Clearing keeps it, so the next selection can start straight away.
 
-<sub>`ui/dr-ui/ui/library.slint:4032`</sub>
+<sub>`ui/dr-ui/ui/library.slint:3958`</sub>
 
 ### Select everything the grid is showing
 
@@ -153,4 +153,4 @@ Distinct from Done, which leaves the mode entirely. Clearing keeps it, so the ne
 
 A scoped grid of two hundred frames is two hundred taps otherwise, and "all of them, except those three" is a far more common shape than the taps it took to say it.
 
-<sub>`ui/dr-ui/ui/library.slint:4049`</sub>
+<sub>`ui/dr-ui/ui/library.slint:3975`</sub>