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.

crates/steep-server/src/schemas/review.rs

@@ -1,6 +1,7 @@
 use jiff::Timestamp;
+use serde::Serialize;
 
-#[derive(Debug, toasty::Model)]
+#[derive(Debug, toasty::Model, Serialize, Clone)]
 pub struct Review {
     #[key]
     #[auto]