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]>

scripts/mosaic

@@ -11,6 +11,10 @@
 # repository-local and only reachable as scripts/mosaic.
 set -euo pipefail
 REPO="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+# No argument: the full-screen app on a terminal (packages/cli/README.md).
+if [ $# -eq 0 ]; then
+  exec node "$REPO/packages/cli/src/cli.mjs"
+fi
 if [ "${1:-}" = queue ]; then
   shift
   exec node "$REPO/packages/queue/src/cli.mjs" "$@"