fix(424): add throttled field to all StoryAgent ctors and handle HardBlock in ws.rs

The initial commit added the `throttled` field to `StoryAgent` but missed
several construction sites in lifecycle.rs, test_helpers.rs, and scan.rs.
Also adds the `HardBlock` match arm in the WebSocket event conversion and
minor CSS/import ordering fixes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/http/ws.rs

@@ -158,8 +158,8 @@ impl From<WatcherEvent> for Option<WsResponse> {
             }),
             WatcherEvent::ConfigChanged => Some(WsResponse::AgentConfigChanged),
             WatcherEvent::AgentStateChanged => Some(WsResponse::AgentStateChanged),
-            // MergeFailure, RateLimitWarning, and StoryBlocked are handled by the
-            // chat notification listener only; no WebSocket message is needed for the frontend.
+            // MergeFailure, RateLimitWarning, StoryBlocked, and RateLimitHardBlock are handled
+            // by the chat notification listener only; no WebSocket message is needed for the frontend.
             WatcherEvent::MergeFailure { .. } => None,
             WatcherEvent::RateLimitWarning { .. } => None,
             WatcherEvent::StoryBlocked { .. } => None,