Clipboard staging lifecycle and loud degraded pastes

Fills the gap: eager staging at copy time, at most the current copy
kept (sweep at launch and each copy against pasteboard references,
surviving relaunch), and attachment-less fallback pastes surface a
one-shot banner naming the loss.

Claude-Session: https://claude.ai/code/session_01HJ7PhFNmQ19bvy9RMD6GSb

DESIGN/04-interactions.md

@@ -23,7 +23,7 @@ Selection, drag & drop, keyboard, clipboard, search. This is where the old app s
 
 ## Clipboard
 
-- ⌘X/⌘C/⌘V on cards **and lanes** (resettled — lanes joined the clipboard so cross-board structure transfer has a keyboard path under the every-function contract; the cards-XOR-lanes selection rule means the clipboard holds cards or lanes, never both). Hybrid clipboard: pasteboard carries a JSON manifest + plain text; full folder snapshots staged in Application Support so paste reproduces the item byte-for-byte — cards, attachments and all — across boards. Each manifest entry embeds the full `index.md` as a staging-less fallback (a lane entry embeds its cards' too, attachment-less).
+- ⌘X/⌘C/⌘V on cards **and lanes** (resettled — lanes joined the clipboard so cross-board structure transfer has a keyboard path under the every-function contract; the cards-XOR-lanes selection rule means the clipboard holds cards or lanes, never both). Hybrid clipboard: pasteboard carries a JSON manifest + plain text; full folder snapshots staged in Application Support so paste reproduces the item byte-for-byte — cards, attachments and all — across boards. Each manifest entry embeds the full `index.md` as a staging-less fallback (a lane entry embeds its cards' too, attachment-less). **Staging lifecycle** (settled): snapshots are staged **eagerly at ⌘C/⌘X time** — copy captures the source as it is at the gesture, immune to later deletion or unmount — and the store holds at most the *current* copy: a new Lanework copy replaces the previous snapshot, and a sweep at launch and on each copy purges entries the pasteboard no longer references (another app taking the pasteboard orphans the snapshot; the next sweep collects it). The snapshot survives relaunch exactly as long as the pasteboard still points at it — a copy made before quitting pastes whole after restart. **A degraded paste is loud, never silent** (the banner vocabulary — 02-architecture.md): if the staged snapshot is missing or unreadable at paste time, paste falls back to the embedded `index.md` — content intact, attachments absent — and a one-shot banner names exactly what was lost ("Pasted 'Fix login' without its 3 attachments"); the user never discovers an empty `attachments/` later.
 - **Cut is Finder-style deferred**: cut items dim in place until paste moves them; voided if another app takes the pasteboard or the source board closes; second paste materializes copies. **Deletion voids per item**: a cut item that is tombstoned or vanishes externally before paste drops out of the pending cut — 02-architecture.md's UUID-set rule; transient state never resurrects what's gone — so paste moves only the survivors, and a cut voided down to nothing is simply void (paste disabled, no error).
 - Paste lands after the anchor card (or appends to a selected lane). Copies keep `created` (a duplicate is a fork) and take fresh GUID/`order`/`modified`.
 - **Lane paste** lands after the anchor lane — the selected lane, or the selected card's lane; nothing selected = the board's right end. Semantics mirror the drag pair above exactly: a pasted *copy* takes fresh GUIDs throughout and **strips tombstoned cards**; a cut-paste is the ⌘-drag move — the folder moves whole, tombstoned cards landing in the destination's trash.