Realign code with the 2026-07-31 findings-resolution rulings

The full bullet list from Implementation card bf080d9a — both ruling
batches, including the three appended mid-session by 16ef377:

- Restore subjects compose the inverse, never nest: crossing "Undo: S"
  emits "Redo: S" and vice versa; parity, not stack depth, reads a
  legacy double prefix (GitHistoryProvider.restoreSubject).
- Git-operation failures join the one-shot failure banner tier:
  BannerCenter.GitFailureBanner (undo/redo/branchSwitch/addGit), error
  tone at failure rank merged with write one-shots by recency; the
  postLoss compromise is retired at both AppModel wirings.
- order/schema optional below the board root: append-at-end reading
  (ordered siblings first, folder-name tie-break among the order-less),
  schema reads 1, both coerce-tier logged; the root keeps its
  requirements. Ranks.resolvedOrders materializes finite ranks so
  models and placement math stay untouched; first Writer rewrite
  stamps a real rank on touch, placement against an order-less sibling
  stamps that sibling inline in the same bracket. Agent guide v10
  teaches optional keys and zero-read filing. Hostile-YAML order
  shapes become coercion tests; Fixtures/Valid/optional-keys.kanban
  replaces the four retired Malformed boards.
- .gitignore is the relocation-heal noise gate: GitignoreRules pure
  matcher (standard semantics, board-root file only), loader consults
  it once per walk so matched loose files keep the stray posture;
  seeded (.DS_Store + .*.lanework-*) at board creation and template
  instantiation, healed in when missing at open — repo-nested
  included; empty file honored, existing files never edited; the
  committer's obedience via libgit2 status is pinned by test.
- Comments crash-residue sweep gates on step ownership: HistoryStep
  derives backing from its own undo expectations, backedContent unions
  both stacks, the sweep purges per-entry only what no live step owns.
- Skip-purge decoupled (16ef377): a stale-skipped coarse step strands
  whole in NativeHistoryProvider.strandedSteps — still backing, retired
  only at session end; clean exits purge as before.
- Coarse close step named "Changes to '<card>'"; the fine body-edit
  wording never leaks onto the board menu.
- Branch-switch settle clears every open card window's fine stack on
  Save All and Discard alike; the empty fold registers no coarse step.
- Close flush awaits its covering snapshot (quiesce + one generation
  bump, 1s bound), and an explicit flush now queues behind an
  in-flight one instead of skipping — the audit-caught interleaving
  could lose a close flush permanently when the debounce fired inside
  the close sequence; regression tests force both races.
- Commit comment bullets sort chronologically by created, not UUID.
- The production-unwired CardBodyEditSession.editSessionDidChange seam
  is deleted with its seam-only tests.
- Composition-root pins: beginSession composes the committer with the
  store's own EchoLedger and binds the announcer (the miswire class).
- Deliberate 06 conformance pass over every 2026-07-31-tagged
  sentence: fixed Change-custom-key subjects (the retired named
  generic was the only producer), the unbuilt Replace attachment
  vocabulary, heal commits now authored Lanework Integrity, the config
  reader scopes identity to plain [user] sections, add-git re-runs
  detection at create (a stale mode-none could initialize inside the
  user's repo), and add-git failures answer at the form or the banner.
  Structural residue filed on the Redesign board.

2554 tests / 439 suites green.

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

KanbanTests/CommentThreadTests.swift

@@ -273,17 +273,23 @@ struct CommentDefectToleranceTests {
 @Suite("Comments ▸ the kind: comment field table")
 struct CommentFieldTableTests {
 
-    @Test("schema is the only required field — never order, never title")
+    /// A comment carries no `order` and never gains one ("Ordering is chronology, not ranks"), and
+    /// since 2026-07-31 its `schema` is optional too — it sits below the board root like everything
+    /// else, so an absent one reads as 1. What still refuses is a schema **newer than this app**,
+    /// which is the one `schema` rule that is level-blind.
+    @Test("No field is required — order is meaningless here, schema defaults to 1")
     func requiredFields() throws {
-        #expect(IntegrityRules.requiresOrder(.comment) == false)
-
-        let withoutOrder = Data("---\nschema: 1\nkind: comment\n---\nbody\n".utf8)
-        #expect(throws: Never.self) {
-            try IntegrityRules.validateIndex(withoutOrder, path: "index.md", kind: .comment, supportedSchema: 1)
+        for frontmatter in ["schema: 1\nkind: comment", "kind: comment"] {
+            #expect(throws: Never.self) {
+                try IntegrityRules.validateIndex(
+                    Data("---\n\(frontmatter)\n---\nbody\n".utf8),
+                    path: "index.md", kind: .comment, supportedSchema: 1
+                )
+            }
         }
-        let withoutSchema = Data("---\nkind: comment\n---\nbody\n".utf8)
+        let newer = Data("---\nschema: 99\nkind: comment\n---\nbody\n".utf8)
         #expect(throws: BoardLoadError.self) {
-            try IntegrityRules.validateIndex(withoutSchema, path: "index.md", kind: .comment, supportedSchema: 1)
+            try IntegrityRules.validateIndex(newer, path: "index.md", kind: .comment, supportedSchema: 1)
         }
     }