Realign the width and lane-move commands — three fresh settlements

DESIGN edits landing from the parallel session, honored:

- Caret chords yield to any focused text control (04 ▸ Grammar): Move
  Left/Right ⌘←/⌘→ and the width pair ⌥⌘←/⌥⌘→ now disable while the board
  popover is open — its fields are the one non-inline text surface a board
  window has today; the search field and card-window fields extend the rule
  with their own cards.
- The width pair batches over a multi-lane selection (03 ▸ Lane, the styling
  precedent): each selected lane steps one unit through one bracket
  (stepLaneWidths); floor members hold on a decrease; the context-menu
  stepper stays single-lane by nature.
- A width write landing on 1 removes the width key (03 ▸ Lane, the
  remove-at-default family), every mechanism alike — writeLaneWidths is the
  one commit point; a hand-written width: 1 is preserved by the unchanged
  guard until the app itself next edits width.

Claude-Session: https://claude.ai/code/session_01SR4XGjmBE16ZUYWpfFHXwY

Kanban/LiveStore/BoardStore.swift

@@ -678,19 +678,54 @@ public final class BoardStore {
     /// second thing to do about it. The lane stays at its old width, which is the truth — nothing was
     /// written.
     public func setLaneWidth(_ id: ItemID, units: Int) {
-        let clamped = max(1, units)
-        guard let lane = snapshot.lanes.first(where: { $0.id == id }),
-              LaneLayoutMath.displayUnits(of: lane) != clamped
-        else { return }
+        writeLaneWidths([(id, max(1, units))])
+    }
+
+    /// Steps every lane in `ids` one unit — the Increase/Decrease Lane Width menu items' batch
+    /// (03-board-ui.md § Lane, settled: "they batch over a multi-lane selection — each selected
+    /// lane steps one unit, one gesture, one commit"; the context-menu stepper stays single-lane
+    /// by nature and keeps calling `setLaneWidth`).
+    ///
+    /// Lanes already at the one-unit floor simply hold there on a decrease — the batch is not
+    /// refused because one member has nowhere to go, matching the style batch's silent-skip shape.
+    public func stepLaneWidths(_ ids: Set<ItemID>, by delta: Int) {
+        let changes: [(ItemID, Int)] = snapshot.lanes
+            .filter { ids.contains($0.id) && !$0.isDeleted }
+            .map { ($0.id, max(1, LaneLayoutMath.displayUnits(of: $0) + delta)) }
+        writeLaneWidths(changes)
+    }
+
+    /// The one commit point every width mechanism shares — the edge drag, the context-menu stepper,
+    /// and the menu items' batch. One `performWrite` bracket whatever the count: one gesture, one
+    /// app-mediated reload, one commit on git boards (the style batch's rule).
+    ///
+    /// **A width landing on 1 removes the `width` key** (03-board-ui.md § Lane, settled — the
+    /// remove-at-default family beside the empty rename's `title` and the None well's
+    /// `background`): a default lane's frontmatter stays clean whichever mechanism wrote it. A
+    /// hand-written `width: 1` is legal and preserved until the app itself next edits width — the
+    /// unchanged-units guard below skips it, so only a real change reaches the remove.
+    private func writeLaneWidths(_ changes: [(id: ItemID, units: Int)]) {
+        let writes: [(folder: URL, units: Int)] = changes.compactMap { change in
+            guard let lane = snapshot.lanes.first(where: { $0.id == change.id }),
+                  LaneLayoutMath.displayUnits(of: lane) != change.units
+            else { return nil }
+            return (rootURL.appendingPathComponent(change.id.rawValue), change.units)
+        }
+        guard !writes.isEmpty else { return }
 
-        let folder = rootURL.appendingPathComponent(id.rawValue)
         // The closure's signature is spelled out because of `try?`: with the error discarded at the
         // call site Swift stops inferring the typed `throws(BoardWriteError)` and widens it to `any
         // Error`, which `performWrite` will not take. Same wart as the value-returning call sites
         // `performWrite`'s doc comment records, arriving from the other direction.
         try? performWrite { () throws(BoardWriteError) -> Void in
-            try BoardWriter.updateIndex(inItemFolder: folder, operation: .resize(title: nil)) { document in
-                document.set(FrontmatterKeys.width, to: .int(clamped))
+            for write in writes {
+                try BoardWriter.updateIndex(inItemFolder: write.folder, operation: .resize(title: nil)) { document in
+                    if write.units == 1 {
+                        document.remove(FrontmatterKeys.width)
+                    } else {
+                        document.set(FrontmatterKeys.width, to: .int(write.units))
+                    }
+                }
             }
         }
     }

Kanban/UI/Board/BoardCommands.swift

@@ -202,22 +202,35 @@ struct MoveCardCommands: View {
 /// **Never into the trash** costs nothing: the quasi-lane is not in the live lane order, so a step
 /// past the last real lane is simply off the end — which is also the disable rule at the walls,
 /// following the width stepper's floor style rather than letting the store no-op silently.
+///
+/// **Caret chords yield to any focused text control** (04-interactions.md ▸ Grammar, settled):
+/// ⌘←/⌘→ are the standard line-start/end chords, and an enabled key equivalent fires before a
+/// field ever sees the key. The inline title editors are covered by `acceptsBoardMutations`; the
+/// board popover's fields are covered by disabling while the popover is open at all — coarser than
+/// per-field focus, but the popover is a configuration surface (04's carve-out) and no lane move
+/// belongs under it. The search field (m5-search) and the card window's fields (whose windows never
+/// publish a `boardStore` in the first place) extend the same rule with their own cards.
 struct MoveLaneCommands: View {
 
     @FocusedValue(\.boardStore) private var store
+    @FocusedValue(\.boardInfo) private var boardInfo
 
     var body: some View {
         Button("Move Left") {
             move(by: -1)
         }
         .keyboardShortcut(.leftArrow, modifiers: .command)
-        .disabled(destination(-1) == nil)
+        .disabled(caretChordsYield || destination(-1) == nil)
 
         Button("Move Right") {
             move(by: 1)
         }
         .keyboardShortcut(.rightArrow, modifiers: .command)
-        .disabled(destination(1) == nil)
+        .disabled(caretChordsYield || destination(1) == nil)
+    }
+
+    private var caretChordsYield: Bool {
+        boardInfo?.isPresented == true
     }
 
     /// The sole selected live lane and the display slot one step would put it in — `nil` when there
@@ -404,48 +417,60 @@ struct BoardStyleCommand: View {
 /// size — window-growing behaviour belongs to the right-edge drag alone — and they are uncapped, so
 /// widths beyond what the screen can fit stay reachable here even though the drag hard-stops.
 ///
-/// **Validation is the sole-selected-lane rule.** Both items are enabled only when the focused
-/// board's selection resolves to exactly one live lane; a card selection, a multi-selection, a
-/// trash-side selection and an empty one all disable them. Decrease additionally disables at one
-/// unit, which is the floor.
+/// **They batch over a multi-lane selection** (03-board-ui.md § Lane, settled — the styling
+/// precedent): each selected lane steps one unit, one gesture, one commit
+/// (`BoardStore.stepLaneWidths`); the context-menu stepper stays single-lane by nature. A card
+/// selection, a trash-side selection and an empty one all disable them. Decrease additionally
+/// disables when **every** selected lane is at the one-unit floor — a mixed batch stays live, its
+/// floor members simply holding (the style batch's silent skip).
+///
+/// **⌥⌘←/⌥⌘→ yield to any focused text control** (04-interactions.md ▸ Grammar's caret-chords
+/// rule) — see `MoveLaneCommands`, whose ⌘←/⌘→ carry the same obligation and whose doc comment
+/// carries the mechanism.
 struct LaneWidthCommands: View {
 
     @FocusedValue(\.boardStore) private var store
+    @FocusedValue(\.boardInfo) private var boardInfo
 
     var body: some View {
         Button("Increase Lane Width") {
             step(by: 1)
         }
         .keyboardShortcut(.rightArrow, modifiers: [.option, .command])
-        .disabled(selectedLane == nil)
+        .disabled(caretChordsYield || selectedLanes.isEmpty)
 
         Button("Decrease Lane Width") {
             step(by: -1)
         }
         .keyboardShortcut(.leftArrow, modifiers: [.option, .command])
-        .disabled(!canDecrease)
+        .disabled(caretChordsYield || !canDecrease)
     }
 
-    /// The sole selected live lane, or `nil` — the whole of these items' validation.
+    private var caretChordsYield: Bool {
+        boardInfo?.isPresented == true
+    }
+
+    /// The selected live lanes, in snapshot order — the batch, and the items' validation.
     ///
     /// The lock and the open-editor rule are folded in through `acceptsBoardMutations` rather than
     /// left for the write to refuse: an item that is going to fail should not look available.
-    private var selectedLane: Lane? {
-        guard let store, store.acceptsBoardMutations else { return nil }
+    private var selectedLanes: [Lane] {
+        guard let store, store.acceptsBoardMutations else { return [] }
         let selection = store.selection
-        guard selection.liveness == .live, selection.ids.count == 1, let id = selection.ids.first else { return nil }
-        return store.snapshot.lanes.first { $0.id == id && !$0.isDeleted }
+        guard selection.liveness == .live, !selection.isEmpty else { return [] }
+        return store.snapshot.lanes.filter { selection.ids.contains($0.id) && !$0.isDeleted }
     }
 
-    /// A one-unit lane cannot shrink: `width` is ≥ 1 (03-board-ui.md § Lane), and an item whose only
-    /// outcome is a no-op reads better disabled than dead.
+    /// `width` is ≥ 1 (03-board-ui.md § Lane), and an item whose only outcome is a no-op reads
+    /// better disabled than dead — which for a batch means *some* member must have room to shrink.
     private var canDecrease: Bool {
-        guard let lane = selectedLane else { return false }
-        return LaneLayoutMath.displayUnits(of: lane) > 1
+        selectedLanes.contains { LaneLayoutMath.displayUnits(of: $0) > 1 }
     }
 
     private func step(by delta: Int) {
-        guard let store, let lane = selectedLane else { return }
-        store.setLaneWidth(lane.id, units: LaneLayoutMath.displayUnits(of: lane) + delta)
+        guard let store else { return }
+        let lanes = selectedLanes
+        guard !lanes.isEmpty else { return }
+        store.stepLaneWidths(Set(lanes.map(\.id)), by: delta)
     }
 }

KanbanTests/LaneWidthWriteTests.swift

@@ -114,14 +114,16 @@ struct LaneWidthWriteTests {
         defer { fixture.tearDown() }
         let store = try BoardStore(rootURL: fixture.root)
 
-        // Lane two is at 3×, so a clamped 1 is a real change and actually reaches disk.
+        // Lane two is at 3×, so a clamped 1 is a real change and actually reaches disk — where the
+        // remove-at-default rule turns it into an absent key (03-board-ui.md § Lane, settled), which
+        // the read side displays as one unit.
         store.setLaneWidth(ItemID(rawValue: Ident.lane2), units: 0)
-        #expect(try loadedLane(Ident.lane2, in: fixture).width == .valid(1))
+        #expect(try loadedLane(Ident.lane2, in: fixture).width.isMissing)
 
         try fixture.item(Ident.lane2, laneText(order: "2048", title: "Doing", width: "3"))
         let reopened = try BoardStore(rootURL: fixture.root)
         reopened.setLaneWidth(ItemID(rawValue: Ident.lane2), units: -7)
-        #expect(try loadedLane(Ident.lane2, in: fixture).width == .valid(1))
+        #expect(try loadedLane(Ident.lane2, in: fixture).width.isMissing)
     }
 
     @Test("A lane that is not in the snapshot is a no-op")
@@ -160,6 +162,58 @@ struct LaneWidthWriteTests {
         #expect(try fixture.entryNames(Ident.lane1) == ["index.md"], "no temp-file residue either")
     }
 
+    @Test("A width landing on one removes the key — the remove-at-default family")
+    func landingOnOneRemovesTheKey() throws {
+        let fixture = try makeBoard()
+        defer { fixture.tearDown() }
+        let store = try BoardStore(rootURL: fixture.root)
+
+        // Lane two carries `width: 3`; stepping it down to one must not leave `width: 1` behind —
+        // "a default lane's frontmatter stays clean, drag, stepper, and menu items alike"
+        // (03-board-ui.md § Lane, settled). The read side then displays one unit off the absent key.
+        store.setLaneWidth(ItemID(rawValue: Ident.lane2), units: 1)
+
+        let after = try fixture.indexText(Ident.lane2)
+        #expect(!after.contains("width"))
+        #expect(try loadedLane(Ident.lane2, in: fixture).width.isMissing)
+    }
+
+    @Test("A hand-written width of one is preserved until the app itself next edits width")
+    func handWrittenOneIsPreserved() throws {
+        let fixture = try makeBoard()
+        defer { fixture.tearDown() }
+        try fixture.item(Ident.lane1, laneText(order: "1024", title: "Todo", width: "1"))
+        let store = try BoardStore(rootURL: fixture.root)
+        let before = try fixture.indexData(Ident.lane1)
+
+        // Displays one unit, asked for one unit: the unchanged-units guard fires before the
+        // remove-at-default rule can, so the legal hand-written `width: 1` stays byte-for-byte.
+        store.setLaneWidth(ItemID(rawValue: Ident.lane1), units: 1)
+        #expect(try fixture.indexData(Ident.lane1) == before)
+    }
+
+    @Test("The menu batch steps every selected lane one unit in one bracket, floor members holding")
+    func batchStepsEverySelectedLane() throws {
+        let fixture = try makeBoard()
+        defer { fixture.tearDown() }
+        let store = try BoardStore(rootURL: fixture.root)
+        let ids: Set<ItemID> = [ItemID(rawValue: Ident.lane1), ItemID(rawValue: Ident.lane2)]
+
+        // Lane one displays 1× (no key), lane two 3×: one decrease holds the floor member and
+        // steps the other — "each selected lane steps one unit, one gesture, one commit"
+        // (03-board-ui.md § Lane, settled).
+        store.stepLaneWidths(ids, by: -1)
+        #expect(try loadedLane(Ident.lane1, in: fixture).width.isMissing, "held at the floor, key never materializes")
+        #expect(try loadedLane(Ident.lane2, in: fixture).width == .valid(2))
+
+        // A fresh store, because the step reads the snapshot and the first write's reload is the
+        // watcher's (async) — the second gesture in a real session steps off the reloaded board.
+        let reopened = try BoardStore(rootURL: fixture.root)
+        reopened.stepLaneWidths(ids, by: 1)
+        #expect(try loadedLane(Ident.lane1, in: fixture).width == .valid(2))
+        #expect(try loadedLane(Ident.lane2, in: fixture).width == .valid(3))
+    }
+
     @Test("A readable-but-uneditable lane refuses the write, banners it, and keeps its bytes")
     func uneditableLaneBannersAndChangesNothing() throws {
         let fixture = try makeBoard()