A picture off the pasteboard becomes a card's file, its hero, or the board's backdrop

⌘V grows an image-data branch, below the app's own clipboard format and refused
outright while a file URL is on the pasteboard: a screenshot or a browser's Copy
Image lands as "Pasted Image.png" in the anchor card's attachments/, through the
very import path Finder file drops and ⇧⌘A take — one bracket, one Finder-style
collision ladder, one set of banners, and the same silence a drop's arrival has.
A card window's ⌘V pastes onto its own card; a focused text field still wins the
selector natively. A file-shaped flavor travels byte for byte, PNG preferred when
several are offered; TIFF and BMP are re-encoded to PNG, being interchange
encodings rather than files anyone wants in a folder.

The hero key gets the setter it was born owing: "Set as Hero" on any image row of
the attachment list, "Remove Hero" on the row that holds it, with menu-bar twins
so the context entry is nobody's only home. It writes as a restyle — one key, one
bracket, one invertible step on the window's own stack — and replaces rather than
refusing, because a card has one hero and the row that has it says Remove instead.

Edit ▸ Paste as Board Background is the same payload's other destination, taking
the existing background.image convention at its word: the picture into the board
folder as "Pasted Background.png", the colour subkey untouched, the generator's
overwrite-our-own-name rule inherited and its echo memo taught to tell the two
producers apart.

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

Kanban/UI/Board/PasteTarget.swift

@@ -60,6 +60,25 @@ enum PasteTarget {
         return Cards(laneID: lane.id, index: index)
     }
 
+    /// **Which card an image paste lands on** — the anchor card, and only a card (04-interactions.md
+    /// ▸ Clipboard, the image-data branch ruled 2026-08-09: "paste targets a card … per the existing
+    /// paste-target grammar").
+    ///
+    /// `flattenAnchor` again rather than a rule of its own, because the ruling says "the existing
+    /// paste-target grammar" and this is it: the last selected card in flatten order, which is
+    /// already what a card payload anchors after and what ⌘N creates after.
+    ///
+    /// **`nil` wherever the anchor is not a card**, which is the whole of the difference from
+    /// `cards(selection:lastActiveLaneID:snapshot:)` — and the reason there is no last-active-lane
+    /// fallback here. A board payload can *append to a lane*, so "nothing selected" still has an
+    /// answer; a picture has to land in some card's `attachments/`, and there is no card the app
+    /// could pick without inventing one. So an empty selection, a lane selection and a trash
+    /// selection all answer `nil`, the menu greys out, and the user selects a card — rather than a
+    /// screenshot silently arriving on whichever card the app guessed at.
+    static func card(selection: ItemReferenceSet, snapshot: BoardModel) -> ItemID? {
+        NewCardTarget.flattenAnchor(selection: selection, snapshot: snapshot)?.anchorCardID
+    }
+
     /// The lane payload's slot among the board's live lanes — **always an answer**, zero-lane board
     /// included, because lane paste "stays enabled and lands at the board's right end" whatever the
     /// board holds. That is what makes it the other way out of a board with no lanes.