Review: guides on hidden or locked layers, and through layer commands

- Guides on a hidden or locked layer leave the selection (Selection::prune,
  run after every edit and selection change), their Layers rows neither
  select nor drag them, and guide.move / guide.remove / guide.setLayer
  refuse them; guide.setLayer refuses a locked target layer, as dragged
  rows are refused there.
- A new guide goes where new art goes (the current layer, else the top
  shown and unlocked one; refused when there is none), so it never lands
  on a hidden layer and vanishes.
- Layer commands keep guides with their layers: Duplicate (and Alt-drag
  copies of rows) copy a layer's guides onto the copy, Merge Selected and
  Flatten Artwork put the merged layers' guides on the merged layer and
  Flatten discards a hidden layer's. One shared doc predicate for "the
  layer a guide is on"; the deleted-layer cleanup moves into the doc.
- Tests: engine tests for the above and their undo, a doc check that an
  old guide reads with no layer and none is written, and a headless
  Layers panel test of guide rows (select, drag to another layer, locked).
- Translations for the new message; docs and a ROADMAP progress line.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/control-protocol.md

@@ -259,8 +259,10 @@ perspective, Cmd on a side shears).
 Ruler guides are layer objects: `guide.add` puts a guide on the current layer (or `layer`), where it shows, hides,
 locks and is deleted with its layer and is listed in the Layers panel (a click on its row selects it, a drag onto
 another layer's rows moves it there); `guide.setLayer {index?, indexes?, layer}` moves guides to another layer, and
-`guide.list` gives each guide's `layer`, `shown` and `editable`. Guides in files saved before guides had layers go on
-the top visible, unlocked layer when the document opens.
+`guide.list` gives each guide's `layer`, `shown` and `editable`. Guides on a hidden or locked layer leave the selection
+and can't be picked, moved or deleted, and no guide goes onto a locked layer; Duplicate copies a layer's guides, Merge
+Selected and Flatten Artwork keep them on the merged layer (Flatten discards a hidden layer's). Guides in files saved
+before guides had layers go on the top visible, unlocked layer when the document opens.
 
 Floating panels: dragging a dock tab, a panel icon or a popped-out panel's title out of the dock floats that panel
 inside the window, and the strip right of the dock's tabs floats the whole Properties | Layers | Libraries group. A

docs/target-app-parity.md

@@ -411,7 +411,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   - **Temporary tools:** Cmd with any other tool drags with the selection tool used last (Selection, Direct Selection or Group Selection). Held Space pans and Cmd+Space zooms (Cmd+Alt+Space out) whatever the tool.
   - **Panel drag and drop:** art dragged off the canvas onto the Symbols panel becomes a symbol, onto the Swatches panel a pattern swatch and onto the Brushes panel an Art brush; a symbol dragged onto the canvas places an instance where it is dropped, and a brush dragged onto a path is applied to it.
   - **Tool double-clicks:** double-clicking a tool's button opens its options: Hand fits the artboard in the window, Zoom shows 100 %, Rotate, Scale, Reflect and Shear open their Object › Transform dialogs, the Selection, Direct Selection and Group Selection tools the Move dialog (Enter opens these seven tools' dialogs too), Gradient, Eyedropper, Blend and the Liquify tools their panels or options, the Pencil, Paintbrush, Smooth, Blob Brush and Eraser tools their Tool Options (Fidelity, fill, the tolerances, the brush size), and (#812) the Flare tool its Flare Tool Options, the Artboard tool the active artboard's Artboard Options, the graph tools Graph Type for the selected graph, the Symbolism tools the Symbolism Tools Options (Diameter, Intensity, Symbol Set Density) and the Magic Wand tool its panel.
-- **Ruler guides as layer objects:** a guide goes on the current layer, shows, hides, locks and is deleted with it, is listed in the Layers panel (its row selects it) and moves to another layer (`guide.setLayer`, or its row dragged onto that layer's rows); guides from files saved before guides had layers go on the top visible, unlocked layer when the document opens. Not done: guides duplicated with their layer.
+- **Ruler guides as layer objects:** a guide goes on the current layer, shows, hides, locks and is deleted with it, is listed in the Layers panel (its row selects it) and moves to another layer (`guide.setLayer`, or its row dragged onto that layer's rows); guides on a hidden or locked layer can't be selected, moved or deleted, Duplicate copies a layer's guides and Merge Selected and Flatten Artwork keep them on the merged layer; guides from files saved before guides had layers go on the top visible, unlocked layer when the document opens. Not done: guides stacked among the art of their layer (they are listed above it), a guide row's own eye and lock.
 - **Layers panel:** every layer, sublayer, group and object is a clickable row at any depth: a click highlights it and makes its layer current (new art goes there), Shift-click a range, Ctrl/Cmd-click toggles. Sublayers are no longer treated as objects: clicks, marquees, Select All and the Select menu take the art inside them, and each sublayer selects in its own colour. Selection squares on rows with selected art (click selects a row's art, Shift adds or removes; dragging the square moves the selection to another row, Alt copies), the eye and lock on every row with drag-down-the-column (one undo step), Ctrl/Cmd-click an eye for per-layer Outline, Alt-click an eye or lock to hide or lock the other layers (again: show or unlock them all), triangles with Alt to open or close everything inside, drag and drop rows above, below or into layers and groups with a drop line (Alt copies) and a dimmed copy of the row under the pointer (dropped on the trash rows are deleted, on New Layer duplicated, as in Illustrator), inline rename, Delete key on highlighted rows. Buttons and the full panel menu: New Layer/Sublayer (Alt: options, Ctrl: on top), Duplicate, Delete, Options for Selection, clipping mask, isolation, Locate Object, Merge Selected, Flatten Artwork, Collect in New Layer, Release to Layers (Sequence and Build), Reverse Order, Template, Hide/Outline/Lock Others and Show/Preview/Unlock All, Paste Remembers Layers, Panel Options (row size, thumbnails per kind, Show Layers Only). Layer Options: name, colour (presets, each with a chip of its colour, or custom), Template, Lock, Show, Print, Preview (outline drawing and clicking) and Dim Images to %. Every operation is a command (`layer.move`, `layer.highlight`, `layer.merge`…) with validation against cycles and invalid nesting. A document opens with only its top-level layers open; the rows left open are saved in the native file (nothing is written for the default) and reopen that way. Only the rows scrolled into view are laid out, from a row list made once per change: a layer of 5,000 groups of 10 paths, all open, draws the panel in 0.4 ms a frame instead of about 29 s (#638).
 - **Drawing aids:** Smart Guides and snapping (moving, with the Selection, Group Selection or Direct Selection tool, and resizing by the bounding-box handles with the Selection or Free Transform tool, Shift and Alt too: the dragged corner or side lands on the other objects' anchors and centres ("anchor", "center") or lines up with their edges and centres (a line and "align"); with Smart Guides › Spacing Guides, a moved selection that lines up with nothing along an axis lands as far from its neighbour as two other objects of its row or column are apart, or halfway between its two neighbours, the equal gaps marked; with View › Snap to Grid on, a moved selection lands on the grid instead, by whichever of its edges or its centre is nearest a gridline on each axis, #740; the Rotate, Scale, Shear and Reflect tools drag from the anchor they grab and snap the pointer the same way, so a corner dragged onto another object's anchor scales exactly onto it, #482; anchors dragged with Direct Selection: the one pressed on lands on other anchors, its own path's that stay put among them, on path segments or in line with them, the others following, Shift keeps 45° steps, and with Smart Guides off Snap to Point pulls it onto anchors; the Artboard tool snaps artboards, and their bleed, to other artboards, bleeds and art, the grid or whole pixels while moving, copying and resizing them, and the Transform panel shows and edits the active artboard's X/Y/W/H; drawn points, #506: hovering shows where the press goes, the point lands on the other objects' anchors, centres and paths ("anchor", "center", "path") or lines up with their anchors, edges and centres ("align"), the Pen's on the path being drawn too, near a construction guide through the anchor before it on that guide (Preferences › Smart Guides › Construction Guides and Angles), and with Shift kept to its 45° step or a square's diagonal it slides along that way into line; the targets are gathered once per document state, from the art in the window, and the anchors, centres and lines near the pointer are found by bisection, so hovering never rescans the document), guides dragged out of the rulers (#451: they snap as moved guides do, Shift to the ruler's ticks; with the Artboard tool they are artboard guides, which run across their artboard only and move, copy and delete with it, `guide.add {artboard}`) that the Selection, Direct Selection and Group Selection tools then pick and drag (#414: the selected guides highlight and move together, Alt copies them, Shift snaps the dragged one to the ticks, otherwise it snaps to pixels, the grid or the edges, centres (so the sides' midpoints) and anchors of the art and the artboards, or with Smart Guides off Snap to Point pulls it onto anchors; Shift-clicked they join the selected art, and Shift-added art keeps them, so guides and art are selected together in either order, Delete then deleting both in one step; the arrow keys nudge them, Delete deletes them, dragging one back onto its ruler deletes it, Lock Guides and Hide Guides leave them alone; `guide.list`, `guide.select`, `guide.move` and `guide.remove` reach agents), a right-click on either ruler or the origin box to pick the document's units (the current one checked; `document.setUnits`, one undo step, #528), and Draw Normal / Behind / Inside modes.
 - **Views:** the status bar's artboard navigator (first, previous, next, last; `view.goToArtboard`) goes to an artboard and fits it, and Fit Artboard in Window and Actual Size show the navigator's artboard. The Artboards panel highlights that active artboard: clicking a row makes it active (the Artboard tool's too, while it is chosen) as does clicking an artboard with the Artboard tool, double-clicking its number also fits it in the window and double-clicking its name renames it. Duplicate Artboards, or a row dragged onto New Artboard, copies the artboard with its art (#446). Escape leaves Presentation Mode, F from it goes back to Normal Screen Mode, and the screen mode isn't saved with the preferences: the app always starts in Normal Screen Mode with its menus and panels (#472). View › Pixel Preview shows the art as the document pixels it rasterizes to, one per point and hard-edged when magnified, turning with a rotated view (it used to draw the smooth vectors, with only the pixel grid over them).