feat(queue): queue as data A2, migration, render and dispatch (#1508)

Filbert approved round 1 (f167b85e). Manifest 782bcb62, 21 files, plus
the QUEUE.md markers and the TOOLS.md section. Lead decision 35.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/queue/tests/helpers.mjs

@@ -3,7 +3,7 @@
 // the two discord helpers it imports, so the code-under-root check (8.3)
 // passes there and nothing touches this checkout's .git.
 import { spawnSync } from "node:child_process";
-import { cpSync, mkdirSync, mkdtempSync, realpathSync, rmSync, writeFileSync } from "node:fs";
+import { cpSync, mkdirSync, mkdtempSync, realpathSync, rmSync, statfsSync, writeFileSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { dirname, join } from "node:path";
 import { fileURLToPath, pathToFileURL } from "node:url";
@@ -74,6 +74,11 @@ export function queueMd(body = LEGACY) {
 // `scripts`, it also commits queue-commit.sh, the guard and a one-test
 // packages/queue/tests, so the commit procedure has an archive to run.
 export function scratchRepo(t, { map = mapText(), commitMap = true, name = "repo", scripts = false } = {}) {
+  // The CLI refuses tmpfs (N5), and the child-process tests can't pass it a
+  // test layer, so a tmpfs temp directory would fail them all confusingly.
+  if (statfsSync(tmpdir()).type === 0x01021994) {
+    throw new Error(`${tmpdir()} is tmpfs, which the queue refuses; set TMPDIR to a directory on ext4, xfs or btrfs`);
+  }
   const base = realpathSync(mkdtempSync(join(tmpdir(), "mosaic-queue-test-")));
   if (t) t.after(() => rmSync(base, { recursive: true, force: true }));
   const home = join(base, "home");