Place: a file read apart from the session goes only into its document

Session::place_read and Session::place_queue_read placed a file, or
loaded the place cursor, in whichever document was active when the read
finished. A job prepared in one document could land in another one that
was activated meanwhile, or that stayed open after the first was closed.
Replace did not stop it when the other document held an equal object
under the same id.

PlaceJob, QueueJob and QueueRead now keep the uid of the document they
were prepared in. Both calls refuse a read whose document is not the
active one with "the document it was prepared for is no longer active",
before any selection, edit, tool change or journal entry. Switching back
to the original document places the file as before.

docs/target-app-parity.md

@@ -1639,6 +1639,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   - File › Place reads Word 97-2003 `.doc` documents as area type with the same formatting, read from the main text's pieces, the style sheet's paragraph and character styles and direct formatting. Table rows are paragraphs with their cells separated by tabs and fields place as their results; fields without a result, hidden and deleted text, pictures, headers, footers, notes, comments and text boxes are left out, and `warnings` names each kind left out or changed. Encrypted documents, documents last saved with fast save and Word 6.0 and Word 95 documents are refused (`file.place`, `crates/engine/src/tests/textimport.rs`).
   - Placing a Word 97-2003 `.doc` document works out each style's formatting once and each property run's once, and refuses property pages that are out of order, listed twice or overlap, a style sheet that holds fewer styles than it counts, styles based on each other in a loop, and more than 100,000 runs of character or of paragraph properties, 16 MiB of properties or 100,000 paragraphs, hidden ones included (`file.place`, `crates/engine/src/tests/textimport.rs`).
   - On the desktop, File › Place reads and decodes files off the UI thread, one at a time, and places each once it is read, with "Placing" in the status bar and the busy spinner until then: the Place dialog's OK, a file dropped on the canvas, a click or drag of the place cursor, and the OK of the PDF, DXF and text import options. The files and thumbnails the place cursor is loaded with are read the same way, and the Place dialog's lines about its files are read on a thread of their own. Files are placed in the order they were started; a file is not placed while a dialog is open or a drag is under way, and a file whose document was closed meanwhile is not placed. `file.place` and `file.place.queue` over MCP and scripts reply as before.
+  - A file read for `file.place`, or files read for the place cursor, apart from the session (`Session::place_read`, `Session::place_queue_read`) go only into the document they were read for: while another document is active, or once that document is closed, they are refused with "the document it was prepared for is no longer active" and no document, selection, tool or undo step changes (`crates/engine/src/tests/place.rs`).
   - On the desktop, Paste from a menu or shortcut captures another app's bitmap or reads a copied image file on the UI thread, then decodes the image on the file-reading worker. The status bar shows "Pasting" until the image is pasted. Windows device-independent bitmaps and Linux clipboard images are encoded as PNG on that worker. A Copy or Cut made while the image is read keeps its internal clipboard. `edit.paste*` over MCP and scripts reads the bitmap at once.
   - The pixels of a PNG, JPEG, GIF or WebP file that Place decodes to check them are kept in the image store the renderers share, so the canvas's first frame with the placed image draws them without decoding the file again on the UI thread: File › Place, a file dropped on the canvas, a click or drag of the place cursor, `file.place`, and Paste of such an image. A CMYK JPEG is still decoded when it is first drawn (`crates/ui-egui/src/placing.rs`, `crates/render/src/tests.rs`).
   - A photo whose EXIF orientation turns or flips it (a camera held upright or upside down) is placed and opened upright, as it was taken; the image is stored as it is seen (#4284). A quarter turn swaps the resolution's axes, so the image keeps its physical size. TIFFs read without the image decoder (grayscale with extra channels, CCITT Group 3, CMYK with one plane per ink) follow their Orientation tag too, and a turned CMYK JPEG or TIFF keeps its inks, 8 bits each, as a CMYK TIFF.