Add live dashboard with SSE job events

Expose /jobs, /dedup, and /events routes backed by a new EventBus that
broadcasts job lifecycle and per-job progress over SSE. Serve a static
dashboard from front/ that lists pending and in-progress jobs, streams
agent activity, and shows completed reviews.

Also add migrate-apply/migrate-generate scripts that load .env, update
the Containerfile to ship the front assets and use the apply script, and
refresh the roadmap.

scripts/migrate-apply.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+
+if [ -f "${ROOT_DIR}/.env" ]; then
+    set -a
+    # shellcheck disable=SC1091
+    . "${ROOT_DIR}/.env"
+    set +a
+fi
+
+cd "${ROOT_DIR}"
+
+if [ -x "${ROOT_DIR}/steep-server" ]; then
+    exec "${ROOT_DIR}/steep-server" migration apply "$@"
+else
+    exec cargo run -p steep-server -- migration apply "$@"
+fi