The loader collects every fail-fast defect and honors per-open skips

Phase 1 of the decision surface (01 ▸ Malformed input, settled
2026-07-31): BoardLoadFailure aggregates the walk's defects in walk
order — stop-at-first retires. Environmental failures (unreadable root,
not-a-directory) stay immediate single-defect throws: there is no walk
to collect from. A defective root index is recorded and the walk
continues into the children (nothing in the walk consults the parsed
root document — verified); a defective lane, card, or trash-entry index
records and skips its subtree, Re-check's whole-walk re-aggregation
being the designed loop for what hides beneath. load(skipping:) is the
per-open skip channel: a skipped path's item is omitted from the model
and surfaces as LoadWarning.userSkipped; root paths are unskippable by
construction. The reload-breakage banner carries the aggregate ("…and
N more"), single-defect sentences byte-identical to before. Two new
multi-defect fixture boards; suite 2591 green.

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

Fixtures/Malformed/many-defects.kanban/10000000-0000-4000-8000-000000000001/20000000-0000-4000-8000-000000000001/index.md

@@ -0,0 +1,8 @@
+---
+schema: 1
+kind: card
+order: 1024
+title: Intact Card
+---
+Nothing wrong with this one. It is here so the broken sibling below is a *card* defect rather
+than the only thing in its lane.

Fixtures/Malformed/many-defects.kanban/10000000-0000-4000-8000-000000000001/20000000-0000-4000-8000-000000000002/index.md

@@ -0,0 +1,8 @@
+---
+schema: 2
+kind: card
+order: 2048
+title: From A Newer Lanework
+---
+Defect #2: a schema newer than this app, below the root — the one `schema` rule the optional-key
+ruling left alone. Unfixable, so the surface offers only Skip.

Fixtures/Malformed/many-defects.kanban/10000000-0000-4000-8000-000000000001/index.md

@@ -0,0 +1,6 @@
+---
+schema: 1
+kind: lane
+order: 1024
+title: Intact Lane
+---

Fixtures/Malformed/many-defects.kanban/30000000-0000-4000-8000-000000000002/40000000-0000-4000-8000-000000000009/index.md

@@ -0,0 +1,8 @@
+---
+schema: 3
+kind: card
+order: 1024
+title: Hidden Behind The Broken Lane
+---
+Broken too, and deliberately *not* in the aggregate: its lane was skipped before this folder was
+ever listed. Fix the lane and the next walk reports this one.

Fixtures/Malformed/many-defects.kanban/30000000-0000-4000-8000-000000000002/index.md

@@ -0,0 +1,10 @@
+---
+schema: 1
+kind: lane
+order: 2048
+title: A Lane That Will Not Parse
+labels: [red, green
+---
+Defect #3: unparseable YAML — an unterminated flow sequence, the same shape
+`unparseable-yaml.kanban` uses one level up. The card below is never enumerated: a broken lane
+takes its subtree with it, and repair-then-re-check is what reveals what it was hiding.

Fixtures/Malformed/many-defects.kanban/50000000-0000-4000-8000-000000000003/60000000-0000-4000-8000-000000000004/index.md

@@ -0,0 +1,7 @@
+---
+schema: 1
+kind: card
+order: 1024
+title: Last Card
+---
+The walk reaches here, which is the point: a defect in an earlier lane does not end the walk.

Fixtures/Malformed/many-defects.kanban/50000000-0000-4000-8000-000000000003/index.md

@@ -0,0 +1,6 @@
+---
+schema: 1
+kind: lane
+order: 3072
+title: Also Intact
+---

Fixtures/Malformed/many-defects.kanban/index.md

@@ -0,0 +1,8 @@
+---
+title: Many Defects
+created: 2026-07-31T09:00:00Z
+---
+The root's own `schema` is missing — the this-really-is-a-board gate, and defect #1.
+
+The walk does not stop here: lanes are enumerated by folder shape, so everything below is still
+read and reported in the same aggregate.