local-dev: rebuild dead sandbox + harden lobby card UX

Three fixes around the dev sandbox end-to-end path. Each one was
flushed out by an actual login walkthrough after the previous
commit.

Backend bootstrap now treats `cancelled`, `finished`, and
`start_failed` as terminal: the per-boot find-or-create skips such
games and provisions a fresh one. Without this, a single bad
shutdown cascade leaves the developer staring at a dead lobby tile
forever (cancelled games don't transition back). Covered by
TestTerminalSandboxStatus.

Tools/local-dev: stop killing engine containers in `make down`. The
runtime treats the disappearance of an engine as a real failure
(cascading the lobby game to `cancelled`); leaving the container
running across `down/up` lets the runtime reconciler re-attach on
the next boot. The teardown happens only in `make clean`, where the
DB is wiped anyway. Compose now also exposes :9090 (authenticated
EdgeGateway listener) on the host so the Vite dev proxy can reach
the Connect-Web surface, and bumps the gateway anti-abuse limits
for `public_misc` so the same surface is not blanket-rejected with
413.

Ui/frontend: the lobby's `My Games` cards are now clickable only
for the playable statuses (`running`, `paused`, `finished`). All
other statuses render as disabled buttons so a click on a draft or
cancelled game no longer drops the user on a 404 — the in-game
view at /games/:id/* doesn't exist before Phase 10 and never makes
sense for a cancelled game. Vite proxy splits the dev targets so
`/api/*` continues to talk to the REST listener and
`/galaxy.gateway.v1.EdgeGateway/*` is routed to the Connect-Web
listener via VITE_DEV_GRPC_PROXY_TARGET (defaults to :9090).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ui/frontend/src/routes/lobby/+page.svelte

@@ -185,6 +185,16 @@
 		goto(`/games/${gameId}/map`);
 	}
 
+	// Statuses for which the game has a navigable in-game view.
+	// Lobby-internal statuses (draft, enrollment_open, ready_to_start,
+	// starting, start_failed) and terminal ones (cancelled) stay
+	// non-clickable; clicking them otherwise lands on a 404 because
+	// /games/:id/map only meaningfully exists once the runtime has
+	// produced game state.
+	function isPlayableStatus(status: string): boolean {
+		return status === "running" || status === "paused" || status === "finished";
+	}
+
 	onMount(async () => {
 		if (
 			session.keypair === null ||
@@ -259,6 +269,7 @@
 						<button
 							class="card"
 							onclick={() => gotoGame(game.gameId)}
+							disabled={!isPlayableStatus(game.status)}
 							data-testid="lobby-my-game-card"
 						>
 							<strong>{game.gameName}</strong>
@@ -448,6 +459,12 @@
 		width: 100%;
 	}
 
+	button.card:disabled {
+		cursor: not-allowed;
+		color: #777;
+		background: #f0f0f0;
+	}
+
 	li.card {
 		cursor: default;
 	}