feat(cli): full-screen terminal app (#1544, row 55)

Bare `mosaic` on a terminal opens the app. It has Inbox, Tasks, Agents
and Trail screens, help, and a decide overlay, and it uses the alternate
screen, raw mode, resize and SIGTERM, and restores the terminal on exit.
draw(state) in screens.mjs is pure. cli.mjs exports resolveDecision,
which `mosaic decide` and the app share, so both write the same lines
and ask the same question. A decision resolves on `y` only while
decideShown() says the whole decide box is on screen. The app reads that
at the key. A box that doesn't fit is replaced by "Too small to show this
decision", and any key answers No. scripts/mosaic sends no arguments to
packages/cli (a decided scope addition), so the queue dispatch test
follows. The cli README and docs/TOOLS.md describe the app.

Darkwing built it (agents/darkwing/work/queue-55), in three rounds.
Round 3 was approved by Dewey (27308) and Filbert (27309) on manifest
59f1b9b4, 9 paths. Their non-blocking notes go to row 69 (#1562): a
narrow-terminal test for the decideShown MIN_COLS guard, a way out from
the hidden box, a U+18D08 width test, a cut box keeping Esc back, and
the README row count stated as an example.

Sage's gate on 3634d06e, sequential and teed: node suites cli 110 and
queue 150, 0 failed; test-auth 15, test-conductor 17, test-config 24,
test-discord 66, test-extension-package 18, test-foundation 44,
test-queue 27, test-release 14, test-task 98, all 0 failed (Docker on).
122b1223..3634d06e touches none of the 9 paths.

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

packages/cli/src/format.mjs

@@ -66,7 +66,7 @@ export function formatTasks(list) {
     .join("\n")}\n`;
 }
 
-function trailSummary(r) {
+export function trailSummary(r) {
   switch (r.table) {
     case "events":
       return [r.kind, r.actor_role ?? null, r.body?.operation ?? null, r.body?.decision ? `decision ${shortId(r.body.decision)}` : null].filter(Boolean).join("  ");