Moves are not deletions for stamp attribution; re-stamp on move

Resolves the 06-vs-08 contradiction: 06's Lanework External fallback
demotes on true deletions only (id vanished from the board, per the
message engine's whole-board id matching), not folder moves. A bare mv
leaves the moved card unstamped, so 08 now teaches re-stamping on every
move as well as every write.

Claude-Session: https://claude.ai/code/session_01HJ7PhFNmQ19bvy9RMD6GSb

DESIGN/08-agent-integration.md

@@ -9,7 +9,7 @@ AI agents are first-class users of Lanework boards — not through an API, but t
 3. **Fail-fast validation + atomic writes** — a malformed agent write surfaces loudly with the offending path instead of silently corrupting. The right failure mode for letting AI write into a planning system.
 4. **Skip-don't-fail for index-less folders** — an agent interrupted between `mkdir` and writing `index.md` cannot brick the board.
 5. **Git trail** (06-history-undo.md) — on git-enabled boards, agent changes are auto-committed, attributed, and undoable like any others. Foreign changes are committed under a synthetic external author, structurally distinct from the user's own commits; an agent can claim its work lightly by stamping `modified-by` (guarantee 6 below), or precisely by committing its changes itself — the app follows along: a held `index.lock` just makes the auto-committer retry/re-debounce, and a tree the agent already committed is a silent no-op that preserves the agent's authorship (06-history-undo.md). The guide says so, and also tells agents to **stage only their own paths** (no `git add -A`) — a sweep would commit the user's not-yet-auto-committed changes under the agent's name.
-6. **`modified-by` self-stamping** (01-storage-format.md) — the lightweight attribution path: an agent stamps files it writes (`modified-by: <your-name>`), and the stamp renders on the card window's modified line and authors the agent's foreign commits (06-history-undo.md) — no git ceremony, and it works on no-git boards, where it is the *only* attribution there is. The app clears the stamp on its own writes, so agents should re-stamp on every write, not once.
+6. **`modified-by` self-stamping** (01-storage-format.md) — the lightweight attribution path: an agent stamps files it writes (`modified-by: <your-name>`), and the stamp renders on the card window's modified line and authors the agent's foreign commits (06-history-undo.md) — no git ceremony, and it works on no-git boards, where it is the *only* attribution there is. The app clears the stamp on its own writes, so agents should re-stamp on every write, not once — and on every *move*: a bare folder move rewrites nothing, so the moved card arrives unstamped and the commit falls back to the generic external author (06's fallback demotes on unstamped changed files and true deletions; a move is neither stamped nor a deletion until the agent re-stamps it).
 
 ## The agent guide (`CLAUDE.md` at board root)
 
@@ -19,7 +19,7 @@ The app silently maintains a `CLAUDE.md` in every board — a condensed, agent-f
 - Moving between lanes (folder move), reordering (gapped ranks, only touch the moved item).
 - Tombstone deletes, colors/icons.
 - New in the rewrite: **attachments** (the `attachments/` convention, importing files).
-- New in the rewrite: **`modified-by` self-stamping** — stamp files you write; re-stamp every write (the app clears it on its own writes); self-commit instead when you need exact authorship.
+- New in the rewrite: **`modified-by` self-stamping** — stamp files you write; re-stamp every write *and every move* (the app clears it on its own writes; a bare folder move leaves the card unstamped); self-commit instead when you need exact authorship.
 - New in the rewrite: a pointer to the optional **`CLAUDE.user.md`** (see below), instructing agents to read it when present.
 
 Mechanics: version marker in the first line (`lanework-agent-guide vN`); rewritten when missing or older, never downgraded, left untouched when current or newer. To the loader it's just another ignored file.