Print boards and cards with configurable components and named print profiles

⌘P had no story: KanbanApp removed the platform's Print row outright on
11-command-nexus.md's "No Print story in v1 (⌘P unused)" line. That line
retires. File ▸ Print… now prints the board in front — lanes left to right,
each lane's cards top to bottom, as a linear document rather than a picture
of the strip — or, from a card window, that card. The trash is unreachable
by construction: it is a sibling container of `lanes`, not a lane.

The rules live in a pure layer nothing AppKit can reach. `PrintOptions` is
one Codable value carrying the printing card's five bullets — which
components (title, icon+labels line, rendered body, comments off by default
with either reading order), page breaks, one base face and size every other
size derives from, and a toggleable running head and foot. `PrintSource` is
what is being printed, frozen at ⌘P so the panel's repeated relayouts and a
board reloading underneath cannot disagree. `PrintDocumentBuilder` turns the
pair into a block list, which is where every decision a rendered page hides
becomes something a test can hold: component order, comment ordering, and
page-break markers that are markers rather than whitespace. Empty is empty
all the way up — a card with nothing to print consumes no page break, and a
lane whose cards all dropped out takes its heading with it.

A page break is a pagination fact, not a spacing one. TextKit has no
page-break character, so `PrintDocumentView` splits the document into
sections at its breaks and flows each into as many page-sized text
containers as it needs: a container boundary *is* a sheet boundary, at any
paper size with any margins. Bodies come from the app's one Markdown pass —
`BodyMarkup.parse` into `BodyMarkupRenderer` — re-faced run by run so the
chosen family reaches the text and fixed-pitch code keeps its own, and drawn
under a forced light appearance so the card window's dynamic label colours
do not print white.

Options ride in the print panel's own accessory rather than a pre-flight
sheet of ours, which buys the system's live preview of the real paginated
document; the preview refreshes through one KVO revision counter rather than
thirteen mirrored properties. Profiles persist app-side in UserDefaults,
never in board files — a print profile is how this user likes to read, not
what a board is (`BoardZoomStore`'s argument). A name is a profile's
identity, folded case-insensitively; "Last Used" is reserved in every
spelling, kept out of the stored list, and captured when an operation
actually ran, so a cancelled print rewrites nothing. Both decoders are
total: one unrecognized key must not cost a user every profile they saved.

DESIGN/11-command-nexus.md gains the Print row and loses the sentence
saying it would never have one.

Claude-Session: https://claude.ai/code/session_014PtZdPwqZuqEDLc6wZMtEy

Kanban/KanbanApp.swift

@@ -306,11 +306,21 @@ struct KanbanApp: App {
             }
         }
 
-        // "No Print story in v1 (⌘P unused)" (11-command-nexus.md ▸ Standard macOS furniture) — the
-        // system's default Print item is removed outright rather than left dead, since a menu item
-        // with nothing behind it is exactly what the Nexus's "a command absent here doesn't exist"
-        // rules out in the other direction too.
-        CommandGroup(replacing: .printItem) {}
+        // File ▸ Print… (⌘P) — **the app's own row**, replacing the system's nil-target one
+        // (11-command-nexus.md's Print row; the "No Print story in v1 (⌘P unused)" line it retired).
+        //
+        // `replacing: .printItem` rather than an addition, for the same reason Undo/Redo replace the
+        // platform's pair: the standard rows are nil-target actions resolved through the responder
+        // chain, and this app's print target is the *frontmatter-shaped document behind the focused
+        // window*, which no responder vends. Two items sharing the title "Print…" is also exactly what
+        // titles-are-API forbids.
+        //
+        // Page Setup… stays absent with it: the paper questions are answered in the print panel's own
+        // page-setup group (`PrintCoordinator`), so a second dialog would be a second place to set one
+        // margin.
+        CommandGroup(replacing: .printItem) {
+            PrintCommand(appModel: appModel)
+        }
 
         // Help carries "the one line teaching the System Settings remap path" (11-command-nexus.md ▸
         // Standard macOS furniture) — this app's whole Help menu, since there is no other content to