Build AgentGuide — versioned CLAUDE.md maintenance

The app-owned agent guide at every board root (DESIGN/08 ▸ The agent
guide): version-gated by a first-line marker (v5, superseding the
pathfinder's v4 guides on real boards), rewritten when missing or older,
byte-for-byte untouched when current or newer. A markerless CLAUDE.md is
displaced to CLAUDE.user.md when that name is free — never clobbered —
and the guide write is skipped with a log when it isn't. Symlinks,
folders, and read-only volumes are skipped in silence; the write rides
performWrite's bracket as an app-mediated Writer operation (new
WriteOperation.agentGuide), so the echo lands appMediated and the
Pro-era committer can attribute it honestly later.

Hooked at store acquire (beside the loose-file relocation, after the
watcher exists) and on every successful reload — the guide self-heals
from foreign deletion or rollback, pre-wiring 06's acknowledged undo
bounce. The refresh memo arms before each attempt and clears on a
successful write, so a failing write can't hot-loop and a foreign
deletion stays healable. First-line-only marker parsing (no Regex);
guide content is one swappable literal, finalized under the next card.

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

README.md

@@ -46,6 +46,8 @@ Lanework is in early development. This list tracks what has actually shipped and
 
 - **Undo** — ⌘Z and ⇧⌘Z are native macOS undo, per board: one stack owned by the board's session and shared by every window over it, so a card window's ⌘Z crosses the same step the board window's does, and another board's never does. Every app-mediated mutation registers an inverse at the write boundary — create, move, reorder, rename, restyle, resize, delete, and an Edit session's whole run of saves — with a restore registering as the ordinary move it is — one gesture to one step, named in the app's own vocabulary so the Edit menu reads "Undo Move 3 Cards" and the toolbar's twins light up and dim with it. Undoing is a real write, never an in-memory revert: it goes through the same atomic writer, echoes back through the watcher, and refreshes every window. Because the app is not the only writer, each step re-checks its target the moment you press ⌘Z — field by field, against what its own write left — and a step the disk has moved past is **skipped rather than applied**, with a quiet row saying which item changed outside Lanework, while ⌘Z falls through to the next step; a step that merely failed to write (a full disk, an unplugged volume) stays put to be retried. Permanent deletion and the duplicate-id repair are deliberately outside it — the confirmation is the safety — attachment add and remove register nothing in v1, and foreign edits never join the stack. The read-only lock disables Undo and Redo with every other mutating command and gives them back, stack intact, when it clears. The stack lives with the session and dies at close, standard macOS behaviour. Both editions ship it: base runs the native stack, and Lanework Pro binds git behind the same seam without changing a keystroke.
 
+- **The agent guide** — every board root carries a `CLAUDE.md` the app writes and keeps current: a condensed, agent-facing rendition of the schema — the folder layout, ordering arithmetic, creating and moving cards, the `.trash/` convention, `attachments/`, `modified-by` self-stamping, the colour and icon palettes, and the git etiquette — so any file-capable agent dropped into the folder already knows how to work the board. It is app-owned and version-gated by a marker in its first line: rewritten when missing or older, left byte-for-byte alone when current or newer, and re-checked on every reload, so a guide deleted or rolled back from outside heals by itself. A `CLAUDE.md` that isn't the app's is never clobbered — it moves to `CLAUDE.user.md` (the user's own extension point, which the app otherwise never touches), and if that name is taken the app simply doesn't write a guide. A symlink or folder wearing the name is left alone, and a board on a read-only volume is skipped in silence: the guide is a courtesy and never an interruption.
+
 ## Development
 
 The Xcode project is generated — `project.yml` is the source of truth, not the `.xcodeproj`: