Remove the lane header's "+" new-card control

The lane header no longer draws a new-card button. Every other
creation path is untouched: File > New Card (Cmd-N), Return on a
selected lane, and double-click on lane empty space.

- LaneView: drop the button and its overlay slot, leaving the
  collapse chevron as the header's one piece of trailing chrome.
- NewCardTarget: drop the button's click-names-target carve-out over
  the Cmd-N target rule (Return on a selected lane is now the only
  direct-target path left).
- AccessibilityPhrases: drop the button's spoken label.
- BoardMetrics: drop its width reserve; laneHeaderTrailingReserve now
  reduces to the collapse chevron's own reserve.
- DESIGN/03, 04, 10, 11: update the lane title-bar inventory, the
  Cmd-N override clause and search-clearing mechanism list, the
  accessibility tree-shape sentence, and the pointer-grammar row that
  described the button.
- Tests: drop the two pinned accessibility-label tests and the
  newCardButtonReserve assertions; retarget the truncation-headroom
  test at the now-solo laneHeaderTrailingReserve; fix stale doc-quote
  comments and the manual accessibility-verification checklist.

Full KanbanTests suite: 2807 tests, 482 suites, all passing.

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

DESIGN/04-interactions.md

@@ -55,7 +55,7 @@ Every command is a menu item. The full inventory — every command and action, i
 - **⌫/⌘⌫ delete** (resettled 2026-07-28; lanes rejoined 2026-07-29): on cards *and lanes*, a move into the trash (`.trash/`, top position — 03-board-ui.md; a lane travels subtree-intact, `kind: lane` stamped when absent, no dialog — recoverable now, so nothing needs confirming); on a **trash** selection the same chord deletes **permanently** (one Delete vocabulary, staged by place — confirmation per 03's recoverability rule, a lane's alert counting its cards, a mixed trash selection's alert counting both kinds). Selection moves to the deleted item's successor sibling, Finder-style (next card in the lane, next lane on the board; the last sibling's predecessor otherwise; empty container = nothing selected) — repeated ⌫ walks down a lane. **In the trash the successor walk is kind-blind** (ruled 2026-07-31): the next row of either kind, in the same all-rows order plain arrows walk — a successor is a fresh singleton selection, so the landing violates no grammar, and repeated ⌘⌫ empties a mixed trash without dead-ends, each delete confirm-gated per its kind. Deliberate deletes pick a successor; *external* vanishing never does (02-architecture.md's reload-survival rule: the selection just shrinks). **Put Back is retired with the tombstone model** (resettled 2026-07-28): File ▸ Delete is the chord's only owner — no twin menu items, no shared-equivalent routing; restore is drag-out or ⌘X/⌘V (The trash below). Plain ⌫ performs the same delete as fixed grammar (see Grammar above) — there is no Edit ▸ Delete item, so the two Delete-titled homes never collide for title-matched remapping.
 - **Select All**: all visible cards on the board — filter-respecting, like every surface (Search below). **On the active trash side it selects the trash** (resettled 2026-07-28): with the trash visible and a non-empty trash selection, Select All selects all visible trash cards; in every other state, all visible live cards — the container boundary decides which "all" is meant (The trash below).
 - **The contract's one carve-out is configuration** (settled; containers re-ruled 2026-07-31 — the popover/sheet split — and **re-ruled back 2026-08-07**): form-like configuration keeps exactly one home per control, and that home is the **board popover** — rename, styling, branch display and *switching*, branch *creation*, add git, commit identity, ahead/behind with Pull/Push, the status badges; its keyboard path is Board Info (⌘I) plus Tab-reachable controls (10-accessibility.md's Full Keyboard Access). *(For a week, setup lived in a board settings sheet reached by Board ▸ Board Settings…; the split's mechanical argument — setup flows fire confirmation alerts, run inline network probes, and accept drag-in key import, acts that want a surface a stray click can't dismiss — did not survive the cost of a second validated surface for controls a user could otherwise reach directly. 03-board-ui.md ▸ Board settings sheet carries the retirement, and 07-sync-collab.md's credential and SSH surfaces are where the argument gets its next hearing.)* Recurring remote *operations* stay under the contract: Board ▸ Pull and Board ▸ Push are menu items (no default chord, remappable; validation enables them only on remote-backed boards — 07-sync-collab.md).
-- **⌘N target rule** (settled): with a card selected, the new card is created in that card's lane, immediately after it (paste-anchor consistency); with a lane selected, appended at its bottom (Return consistency); **a multi-selection anchors at its last member in flatten order** (settled — lane `order`, then card `order`, the multi-drag order; the same anchor serves paste): creation follows the last selected card, or appends to the last selected lane; the lane header's new-card button **overrides this rule** — the click names its target lane, selection notwithstanding (11-command-nexus.md ▸ Pointer grammar); with nothing selected — or a **trash** selection, which never anchors creation — the **last-active lane** — the lane that most recently held selection or a creation in this window session — falling back to the first lane. Title editor focused; same placeholder/abandon semantics as Return-creation. **Zero-lane board** (hand-made, or every lane deleted): card creation and card paste have no target — New Card, Return-creation, and Paste with a *card* payload disable via menu validation until a lane exists. New Lane (⇧⌘N) is one way in; Paste with a **lane** payload is the other — it stays enabled and lands at the board's right end (the lane-paste rule above), so cross-board structure transfer never needs a lane to exist first.
+- **⌘N target rule** (settled): with a card selected, the new card is created in that card's lane, immediately after it (paste-anchor consistency); with a lane selected, appended at its bottom (Return consistency); **a multi-selection anchors at its last member in flatten order** (settled — lane `order`, then card `order`, the multi-drag order; the same anchor serves paste): creation follows the last selected card, or appends to the last selected lane; with nothing selected — or a **trash** selection, which never anchors creation — the **last-active lane** — the lane that most recently held selection or a creation in this window session — falling back to the first lane. Title editor focused; same placeholder/abandon semantics as Return-creation. **Zero-lane board** (hand-made, or every lane deleted): card creation and card paste have no target — New Card, Return-creation, and Paste with a *card* payload disable via menu validation until a lane exists. New Lane (⇧⌘N) is one way in; Paste with a **lane** payload is the other — it stays enabled and lands at the board's right end (the lane-paste rule above), so cross-board structure transfer never needs a lane to exist first.
 
 ### The trash, keyboard-first (resettled 2026-07-28 — the materialized trash)
 
@@ -85,7 +85,7 @@ Custom shortcuts are **system-native, with no in-app remapping UI**: macOS's App
 ## Search
 
 - Search field invoked with ⌘F (the board toolbar's sole default item; removed from the toolbar, ⌘F surfaces it transiently — 03-board-ui.md ▸ Toolbar; in the **card window**, Edit ▸ Find is find-in-text instead — 05-card-window.md), live filter: cards whose title *and* body both miss the query animate out; case/diacritic-insensitive substring. Scope is **all card content the format makes meaningful** (re-ruled 2026-07-29, superseding title-plus-body-only): title + body today; **comment bodies join when comments ship** — via a search-owned transient comment index, never the snapshot: the first live-query keystroke kicks an async sweep of `comments/*/index.md` bodies (`.draft` and `comments/.trash/` excluded), kept fresh by the same FSEvents stream while a query is active and discarded when it clears — the board walk stays O(cards), 01's window-scoped read untouched; **attributes join as they activate** (title now; labels/tags and their kin are reserved, inert keys this version — nothing to search until a future version gives them life). Attachment filenames stay unsearched. Scope options (content vs attributes, either/or) are WISHLIST #10.
-- The filter is the single source of truth for "what's on the board": layout, drop zones, marquee, ranges, arrow nav, and lane count badges all read it. **A drop under an active filter counts in the rendered space** (ruled 2026-08-06, closing the divergence found 2026-08-01): the zones, the shadow, and the write all resolve through the same filtered list — the position the shadow shows is the landing the write performs (the shipped interim — zones and write counting the unfiltered lane while the slots rendered filtered — was self-consistent but named a position the user could not see; retired). The slot's meaning in the full order is its **visible anchor**: the dropped card enters immediately *after* the slot's visible predecessor — or immediately *before* its visible successor when the slot has none (top of the lane) — and a lane the query emptied appends at its true end; a multi-card drop enters in proposal order beside the same anchor. Hidden cards keep their ranks untouched, never displaced by a gesture that could not see them — and the anchor is what makes the gesture's meaning survive the query's clearing: when the filter lifts, the card sits exactly beside the card it was dropped against. The rendered space means everything rendered — the new-card placeholder occupies its slot for the zones exactly as it does for layout. Hidden cards leave the selection; creating a card clears the search — creation's carve-out exists because a brand-new card must not be born invisible, and it is **stated by mechanism, not by gesture** (settled): *any* user-initiated creation on the board clears the query — ⌘N, Return-creation, the header button, empty-space double-click, paste, and Finder file drops alike — while foreign/agent-filed cards keep riding the live filter (02-architecture.md's derived-result rule). **Rename deliberately gets no carve-out**: a rename committed during an active search re-runs the predicate like any edit — a title that stops matching animates the card out and drops it from the selection, exactly as an agent's edit would; the filter stays a pure predicate with one exception, not two. **Escape is staged** (settled): in a non-empty field it clears the query, focus staying in the field; in an empty field it returns focus to the board; with *board* focus and an active search, one press clears the search and the full board returns — search takes Escape before its clear-selection meaning, which applies only when no search is active. **A lane the query empties keeps its slot** (settled): lanes are never filtered out — an all-misses lane stays on the board at its width with a 0 badge (the count reads the filter, 03-board-ui.md); the search filters cards, and the board's structure is not a search result. **A leaving card stays input-reachable for its out-transition** (settled): marquee and arrow targets deregister when the ~0.28 s animate-out ends, so a card mid-departure is briefly reachable while already out of the selection — accepted: it is literally on screen for that span, and closing the window would teach three input sites a predicate the layout already applied. **An open inline rename survives the filter hiding its card** (settled): the editor is a surface the filter doesn't reach — it stays open and focused, commits by UUID wherever the card lives, Escape abandons; keystrokes are never silently discarded for a card that still exists (the dirty-buffer courtesy), and the vanish-discard rule stays reserved for true liveness flips. The typed-query path can't even occur — focusing the search field is focus loss, which commits the rename first — so the rule covers foreign edits that stop the card matching.
+- The filter is the single source of truth for "what's on the board": layout, drop zones, marquee, ranges, arrow nav, and lane count badges all read it. **A drop under an active filter counts in the rendered space** (ruled 2026-08-06, closing the divergence found 2026-08-01): the zones, the shadow, and the write all resolve through the same filtered list — the position the shadow shows is the landing the write performs (the shipped interim — zones and write counting the unfiltered lane while the slots rendered filtered — was self-consistent but named a position the user could not see; retired). The slot's meaning in the full order is its **visible anchor**: the dropped card enters immediately *after* the slot's visible predecessor — or immediately *before* its visible successor when the slot has none (top of the lane) — and a lane the query emptied appends at its true end; a multi-card drop enters in proposal order beside the same anchor. Hidden cards keep their ranks untouched, never displaced by a gesture that could not see them — and the anchor is what makes the gesture's meaning survive the query's clearing: when the filter lifts, the card sits exactly beside the card it was dropped against. The rendered space means everything rendered — the new-card placeholder occupies its slot for the zones exactly as it does for layout. Hidden cards leave the selection; creating a card clears the search — creation's carve-out exists because a brand-new card must not be born invisible, and it is **stated by mechanism, not by gesture** (settled): *any* user-initiated creation on the board clears the query — ⌘N, Return-creation, empty-space double-click, paste, and Finder file drops alike — while foreign/agent-filed cards keep riding the live filter (02-architecture.md's derived-result rule). **Rename deliberately gets no carve-out**: a rename committed during an active search re-runs the predicate like any edit — a title that stops matching animates the card out and drops it from the selection, exactly as an agent's edit would; the filter stays a pure predicate with one exception, not two. **Escape is staged** (settled): in a non-empty field it clears the query, focus staying in the field; in an empty field it returns focus to the board; with *board* focus and an active search, one press clears the search and the full board returns — search takes Escape before its clear-selection meaning, which applies only when no search is active. **A lane the query empties keeps its slot** (settled): lanes are never filtered out — an all-misses lane stays on the board at its width with a 0 badge (the count reads the filter, 03-board-ui.md); the search filters cards, and the board's structure is not a search result. **A leaving card stays input-reachable for its out-transition** (settled): marquee and arrow targets deregister when the ~0.28 s animate-out ends, so a card mid-departure is briefly reachable while already out of the selection — accepted: it is literally on screen for that span, and closing the window would teach three input sites a predicate the layout already applied. **An open inline rename survives the filter hiding its card** (settled): the editor is a surface the filter doesn't reach — it stays open and focused, commits by UUID wherever the card lives, Escape abandons; keystrokes are never silently discarded for a card that still exists (the dirty-buffer courtesy), and the vanish-discard rule stays reserved for true liveness flips. The typed-query path can't even occur — focusing the search field is focus loss, which commits the rename first — so the rule covers foreign edits that stop the card matching.
 - **Dispatch while the search field is focused** (settled): the field is a *control*, not a content editor — the focused-editor lockdown (Grammar above) does not apply. Text-domain keys route to the field: ⌘A/⌘X/⌘C/⌘V act on the query, plain ⌫ edits the query and never reaches the board, horizontal arrows move the caret. **Every key with the field focused acts on the field — stock NSSearchField behavior, no pass-throughs** (settled): vertical arrows are caret movement, ⇧-arrows select query text, and **Return is a swallowed no-op** (the filter is live, there is nothing to submit — it never reaches the board's rename/create grammar). **Tab is the keep-filter path**: plain key-view traversal moves focus to the board with the query intact, and the whole board grammar (arrows, ⌥↑ escalation, Return, ⌘↩) then applies over the *filtered* board; ⌘F returns to the field. Board menu commands stay enabled and act on the board selection exactly as when the field is unfocused — ⌘N included (creating a card clears the search, above) — **except the caret-chord commands**: Move Left/Right ⌘←/⌘→ and the width pair ⌥⌘←/⌥⌘→ disable while the field is focused (Grammar above, caret-chords rule), so ⌘←/⌘→ stay line-start/end in the query even with a lane selected — and the Delete pair stays unambiguous by construction: plain ⌫ is query editing, ⌘⌫ is File ▸ Delete on the selection, and ⌘Z/⇧⌘Z are the field's own text undo, never git undo (06-history-undo.md ▸ Undo routing's control-class rule).
 
 ## Changes from Kanban