Resolve the second design-review batch and drop the face carousel

Rulings written in place: the drop settle yields to the system drag session
(fly-to-slot deferred to WISHLIST #7) and the held proposal's home is the
app-wide DragSession — rendering the arrangement means rendering the card at
release (03, 02); folder drops refuse at hover with loss-row reporting, created
cards land positionally, N shadows, header resolves topmost, shadow-only
feedback (04); the banner vocabulary gains the warning-tone loss row class
(02); all user-initiated creation clears the search (04); loose files beside a
card's index.md relocate into attachments/ with notice — files-only carve-out,
paste normalizes at the boundary, the agent guide teaches it (01, 04, 08);
dropping a card on the shown trash deletes it, shadow pinned topmost (04);
query-emptied lanes keep their slot, the out-transition stays reachable, an
open rename survives the filter, pasteboard staleness accepted (04).

The face carousel does not carry over: the pathfinder's selection-keyed dual
presentation proved undesirable — one presentation per card, selection changes
styling never geometry; the attachment chip and the card window are the whole
media story (03, 01, 10, 11; the same-day carousel settlements superseded on
their Resolved cards).

Claude-Session: https://claude.ai/code/session_01CqjXB7ASoWtbyoGod68k97

DESIGN/02-architecture.md

@@ -65,7 +65,7 @@ The non-modal banner named throughout the read- and write-side rules above is on
 
 - **Hosted by the window of origin.** Every window hosts a banner strip; a condition surfaces in the window whose action produced it — debounced body save, attachment drop, and raw-source Apply failures in their card window; reload breakage, one-shot write failures, commit failures, and lock states in the board window. A card window that closes while its condition persists re-homes the banner to the board window (the condition is still true; it must stay visible somewhere).
 - **One-shots dismiss, conditions heal.** One-shot failures ("Couldn't move 'Fix login' — disk full") carry an explicit dismiss control and no timeout — an error never evaporates unread. Persistent conditions (reload breakage, suspended auto-commit, read-only locks) have no dismiss: they describe ongoing state, standing until the next success clears them, per the rules above.
-- **Concurrent conditions stack.** The strip presents independent rows, precedence-ordered: **in-progress rows (pinned) >** read-only lock > reload breakage > one-shot write failures > commit and attachment failures **> passive info rows** (the remote-change signpost); newest first within a class. Each row heals or dismisses independently; beyond three rows the remainder collapse behind a "+N more" disclosure. **In-progress rows are exempt from the collapse and don't count toward its budget** (settled): they are the strip's only explanation for a bracket's write lock and for a close/quit deferring teardown, and the copy rows carry the reachable Cancel — a spinner may never hide behind "+N more". They're safe to pin: few at once, self-clearing, **newest first within the class like every other** (ratified — insertion order; the class rarely holds more than two rows, and one ordering rule beats a special case). Passive info rows rank last and may collapse — calm by design, nothing gated on seeing them instantly.
+- **Concurrent conditions stack.** The strip presents independent rows, precedence-ordered: **in-progress rows (pinned) >** read-only lock > reload breakage > one-shot write failures > **loss rows** > commit and attachment failures **> passive info rows** (the remote-change signpost); newest first within a class. **Loss rows are the warning-tone class for non-failure losses** (settled 2026-07-28): content that didn't arrive though nothing failed — a degraded paste, folders skipped from a Finder drop, their future kin. They take the one-shot's lifecycle (dismissable, untimed — a loss the user didn't notice is the harm, so it never auto-expires), rank below the true failures (an action that didn't happen outranks one that partially did), and above the ambient notices. Each row heals or dismisses independently; beyond three rows the remainder collapse behind a "+N more" disclosure. **In-progress rows are exempt from the collapse and don't count toward its budget** (settled): they are the strip's only explanation for a bracket's write lock and for a close/quit deferring teardown, and the copy rows carry the reachable Cancel — a spinner may never hide behind "+N more". They're safe to pin: few at once, self-clearing, **newest first within the class like every other** (ratified — insertion order; the class rarely holds more than two rows, and one ordering rule beats a special case). Passive info rows rank last and may collapse — calm by design, nothing gated on seeing them instantly.
 - **Tones, not components.** The banner has kinds — error, warning, info — sharing layout and the accessibility announcement path (10-accessibility.md). The card window's remote-change signpost (07-sync-collab.md) is this same component in the info tone: visually calm, no error color. **Its lifecycle is the one-shot's — dismissable, untimed** (settled): 07's "transient" means non-modal and non-blocking, never auto-expiring; the strip has exactly two lifecycles (one-shots dismiss, conditions heal) and the signpost doesn't add a third.
 - **In-progress operations are info rows** (settled): bracketed git operations ("Pulling…", "Switching to 'main'…") and long non-git work (big-board Duplicate, template instantiation, large attachment imports, and cross-board transfers — drag copies and moves, staged-clipboard pastes) each show an info-tone row with a spinner — determinate where progress is knowable. Completion clears the row (the VoiceOver completion announcement of 10-accessibility.md rides the same event); failure swaps it for the error row. Sighted and VoiceOver users learn one vocabulary.
 - **Cancel appears on safe copies only** (settled): copy-shaped work — attachment imports, Duplicate, template instantiation, cross-board copies and pastes — carries Cancel, meaning "remove the partial copy, nothing lost"; a cross-board ⌘-drag *move* cancels the same way during its copy phase — the source deletes only after the copy lands, so Cancel leaves the original untouched. Git brackets get no Cancel: seconds long, and aborting a rebase mid-flight is a repair job, not a cancel.
@@ -109,7 +109,7 @@ The old app loaded boards fast enough that the planned SwiftData cache was never
 
 ## Changes from Kanban
 
-- The store's transient-state grab-bag gets an explicit home (settled, m3): **TransientBoardState**, one per store, holding state by how a reload treats it. **Item-referencing sets** — selection, drag membership, the pending cut — share one shape (a UUID set plus the liveness side it lives on) and one constraint rule, *members must exist in the current universe*, applied in two directions by one primitive: a reload re-resolves each set independently against the new snapshot (present on the same effective-liveness side, ancestor-walked), and the search filter constrains the selection to its visible set — **the trashed side has exactly one definition: the set with trash rows** (settled): a card carrying its own `deleted:` under a tombstoned lane is in *neither* universe (03-board-ui.md's ancestor walk subsumes it — no row, no membership), so an anchor or selection can never survive on an item that renders nowhere; universe and rows are one function, never a broader set with a pointer-side subset — the hidden-cards-leave-the-selection rule and the reload-survival rule are one rule, expressed once. **Derived state is stored as its inputs only**: the search query is kept, its result set never is — the predicate re-runs against each snapshot (04-interactions.md's live filter). **The overlays** — transient render state covering the gap between a gesture and its disk echo, each discarding itself at handoff. The **new-card placeholder** is anchored to its lane, not to items: no UUID until the title commits, discarded when a reload drops or effectively tombstones its lane, and handed off by discarding itself the moment the created card's UUID appears in a snapshot. The **held drop proposal** (settled — 03-board-ui.md ▸ Motion) is its kin on the other side of a write: at drag release the proposed arrangement keeps rendering over the snapshot while the move write brackets, and the proposal discards itself when the echo reload lands (positions match, nothing visibly moves); a failed write or a reload that vanishes the dragged items discards it and the board animates back to snapshot order. Trash visibility rides along as a plain per-open value: hidden on every open, never persisted — visiting the trash is an errand, not a layout choice.
+- The store's transient-state grab-bag gets an explicit home (settled, m3): **TransientBoardState**, one per store, holding state by how a reload treats it. **Item-referencing sets** — selection, drag membership, the pending cut — share one shape (a UUID set plus the liveness side it lives on) and one constraint rule, *members must exist in the current universe*, applied in two directions by one primitive: a reload re-resolves each set independently against the new snapshot (present on the same effective-liveness side, ancestor-walked), and the search filter constrains the selection to its visible set — **the trashed side has exactly one definition: the set with trash rows** (settled): a card carrying its own `deleted:` under a tombstoned lane is in *neither* universe (03-board-ui.md's ancestor walk subsumes it — no row, no membership), so an anchor or selection can never survive on an item that renders nowhere; universe and rows are one function, never a broader set with a pointer-side subset — the hidden-cards-leave-the-selection rule and the reload-survival rule are one rule, expressed once. **Derived state is stored as its inputs only**: the search query is kept, its result set never is — the predicate re-runs against each snapshot (04-interactions.md's live filter). **The overlays** — transient render state covering the gap between a gesture and its disk echo, each discarding itself at handoff. The **new-card placeholder** is anchored to its lane, not to items: no UUID until the title commits, discarded when a reload drops or effectively tombstones its lane, and handed off by discarding itself the moment the created card's UUID appears in a snapshot. The **held drop proposal** (settled — 03-board-ui.md ▸ Motion) is its kin on the other side of a write: at drag release the proposed arrangement keeps rendering over the snapshot while the move write brackets, and the proposal discards itself when the echo reload lands (positions match, nothing visibly moves); a failed write or a reload that vanishes the dragged items discards it and the board animates back to snapshot order. **Its home is the app-wide DragSession, not this per-store state** (settled 2026-07-28 — the one overlay that outlives a store's scope): a drag inherently crosses boards, so the hold lives once on AppModel, keyed by board root and snapshot generation; per-store homing would need a store-to-store hand-off mid-gesture for no behavioral gain. The placeholder kinship is semantic — hold, hand off at echo, discard on vanish — not residential. A refused write produces no echo reload, so **a short timeout stands in for the failed-write discard signal** (accepted): the hold snaps back animated when no echo arrives. Trash visibility rides along as a plain per-open value: hidden on every open, never persisted — visiting the trash is an errand, not a layout choice.
 
 ## Open questions