M10.2: Create PDF from multiple files, edited as pages in the Organize grid (#361)

* M10.2: create PDF from multiple files

Create a PDF ▸ Multiple files takes PDFs, images and .txt files, lets the
user reorder them, and makes one combined PDF (a bookmark and an optional
page range per file) or one PDF per file in a chosen folder, never
overwriting what is there.

- create: source_kind() tells PDFs, images and text apart (moved from the shell)
- engine: Session::convert_to_pdf, shared by Open, the dialog and the tool
- automation: doc_create_multiple (combine or separate)
- ui: Multiple files dialog reusing the Combine files list; translations
- parity entry and ROADMAP updated; catalog hashes refreshed

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

* M10.2: multiple files open in the page grid; insert files at any gap

Create a PDF ▸ Multiple files now opens the picked files as one unsaved
document in the Organize page grid instead of a file-list dialog: pages
are removed and reordered there, and Save pages writes what is shown.

- grid: a "+" at every gap inserts files right there; Save pages button
- insert from file: several files in order, images and text converted,
  inserted pages selected
- the file-list dialog is removed; one PDF per file stays in the
  doc_create_multiple tool
- translations, catalog hashes, parity notes and ROADMAP updated

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

* M4: insert files by dropping them on the page grid

On desktop, PDFs, images and .txt files dropped on the Organize page grid
are inserted at the gap under the pointer, in order, and selected; a
dropped file still opens as a document everywhere else.

winit does not report the pointer while files are dragged over the
window on every platform, so a drop waits (up to a second) for the
pointer to show up and otherwise appends at the end.

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

* M4: files dragged over the page grid follow the pointer (macOS)

winit sends no pointer moves while files are dragged over the window, so
egui kept the place the pointer entered at: the insertion bar froze there
and the files were inserted there. During a file drag the pointer is now
read from AppKit (safe objc2 calls, crates already in the tree) and fed
to egui, so the bar and a "+" badge follow the pointer and the files go
where they are released.

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

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: Brandon Thomas <echelon@gmail.com>

parity/acrobat-features.toml

@@ -2638,8 +2638,8 @@ milestone = "M4"
 status = "shipped"
 commands = ["page.insert"]
 tools = ["page_insert_file"]
-evidence = ["crates/organize/src/tests.rs::inserting_pages_from_another_file_is_an_incremental_edit", "crates/ui-egui/tests/editing.rs::inserting_a_file_goes_after_the_selection_and_undoes"]
-notes = ""
+evidence = ["crates/organize/src/tests.rs::inserting_pages_from_another_file_is_an_incremental_edit", "crates/ui-egui/tests/editing.rs::inserting_a_file_goes_after_the_selection_and_undoes", "crates/ui-egui/tests/editing.rs::plus_between_pages_inserts_picked_files_there_in_order"]
+notes = "After the selection (toolbar, File menu) or at any gap of the page grid (a + between pages and at both ends); several files at once, in order; images and .txt files are converted first; the inserted pages end up selected. The page_insert_file tool takes PDFs only. Missing: choosing which pages of the file to insert in the app."
 
 [[feature]]
 id = "organize.insert-from-clipboard"
@@ -2683,11 +2683,11 @@ title = "Insert by dropping files onto the page grid"
 area = "D"
 tier = "P1"
 milestone = "M4"
-status = "planned"
-commands = []
+status = "partial"
+commands = ["page.organize"]
 tools = []
-evidence = []
-notes = ""
+evidence = ["crates/ui-egui/tests/editing.rs::files_dropped_between_pages_are_inserted_there", "crates/ui-egui/tests/editing.rs::files_dropped_before_the_pointer_is_known_wait_for_it", "crates/ui-egui/tests/editing.rs::files_dropped_outside_the_page_grid_still_open_as_documents"]
+notes = "Desktop: PDFs, images and .txt files dropped on the Organize page grid are inserted at the gap under the pointer, in order, and selected (elsewhere a dropped file still opens as a document). While the files hover, a bar at the gap and a + badge follow the pointer; on macOS the pointer is read from AppKit, because the windowing layer sends no moves during a file drag. Missing: on Windows and Linux there is no live position, so the grid is only outlined and the files go to the gap the pointer is at right after the drop (or the end after a second); the web build (dropped files open as documents). Covered by simulated drop events; a real drag from Finder is not in the automated tests."
 
 [[feature]]
 id = "organize.extract-pages"
@@ -6798,12 +6798,12 @@ id = "create.create-multiple"
 title = "Convert many files to PDF in one run"
 area = "J"
 tier = "P1"
-milestone = "M13"
-status = "planned"
-commands = []
-tools = []
-evidence = []
-notes = ""
+milestone = "M10"
+status = "shipped"
+commands = ["create.multiple"]
+tools = ["doc_create_multiple"]
+evidence = ["crates/engine/src/tests.rs::mixed_files_convert_and_combine_in_order", "crates/engine/src/tests.rs::files_that_cannot_be_converted_are_refused_clearly", "crates/automation/tests/automation.rs::creating_from_multiple_files_through_tools", "crates/ui-egui/tests/create.rs::multiple_files_open_as_one_document_in_the_page_grid", "crates/ui-egui/tests/editing.rs::plus_between_pages_inserts_picked_files_there_in_order", "crates/ui-egui/tests/editing.rs::save_pages_writes_what_the_grid_shows"]
+notes = "Create ▸ Multiple files: the picked PDFs, images (PNG, JPEG, JPEG 2000, TIFF, GIF, BMP) and .txt files open as one unsaved document in the page grid, in the order picked (a bookmark per file); there pages are removed, reordered, more files inserted at any gap (a + button, or dropped there), and Save pages writes what is shown. One PDF per file is offered by the doc_create_multiple tool only (mode separate), not in the app. Missing: Office, HTML and Markdown inputs, PDF Portfolio output, per-file image resolution choice, progress and cancel for large batches (conversion runs on the UI thread). The combined file has combine's limits: untagged, no page labels or document info carried over, and its per-file bookmarks are not updated when pages are later moved between files."
 
 [[feature]]
 id = "create.image-conversion-options"