swarm-controller: add GET /api/agents/{hive}/{name}/term/stream

hive-agent already publishes classified TermMsg rows to the core NATS
subject $SWARM.term.{hive}.{agent} -- live only, no retention, by
design. This endpoint subscribes that subject per request and relays
each row over SSE, opaque to this daemon (no TermMsg dependency, same
pass-through shape crate::status already uses for hive snapshots).

No replay/history: the publish side never grew JetStream retention, and
this route's own job (a live tail) never needed it.

swarm-controller/src/main.rs

@@ -50,6 +50,7 @@ mod otel_http_client;
 mod read_policy;
 mod status;
 mod store;
+mod term_stream;
 mod vcs_metrics;
 mod wanted;
 mod webhook;
@@ -1674,6 +1675,7 @@ fn build_app(state: AppState) -> axum::Router {
         .routes(routes!(set_agent_state))
         .routes(routes!(matrix_account::put_matrix_account))
         .routes(routes!(get_hive_wanted))
+        .routes(routes!(term_stream::stream_agent_term))
         .routes(routes!(issue_report::get_repos))
         .routes(routes!(issue_report::get_issue_report_all))
         .routes(routes!(issue_report::get_issue_report))