P1 exit: chat UI, sessions column, agent create — 11 E2E journeys green

- Stream layer: incremental SSE parser tested against bytes captured from
  the REAL gateway (chunking-independent, UTF-8-safe, heartbeat-tolerant);
  Zod gateway event schemas; pure transcript reducer (optimistic send,
  delta streaming, step traces, resume dedupe, error states)
- Same-origin /api proxy route: httpOnly cookie -> bearer, unbuffered SSE
  passthrough; NuqsAdapter in root layout
- Chat workspace: route /claws/{id}/chat/{key} (RSC history + settings),
  WelcomeState with suggested prompts, MessageList (right user bubbles,
  left agent messages, blink caret), collapsible StepTrace, Composer
  (Enter sends, Shift+Enter newline)
- SessionsColumn in 208px SlidePanel (?sessions=1): search, relative
  times, active coral border, new session; /claws/{id} resumes latest or
  opens fresh; minimal create-claw form; rail + button and roster links
- P1 exit E2E: scripted reply streams, tool step trace survives reload,
  separate transcripts across sessions with column switching, create claw
  and chat immediately

83 Rust + 56 frontend unit/component tests + 11 Playwright journeys.

Co-Authored-By: Claude Fable 5 <[email protected]>

frontend/src/components/shell/AgentRosterItem.tsx

@@ -1,10 +1,16 @@
+import Link from "next/link";
+
 import type { Agent } from "@/lib/api/schemas";
 import { Avatar } from "@/components/ui/Avatar";
 
-/** One agent row in the left rail (§4): avatar, name, online dot. */
+/** One agent row in the left rail (§4): avatar, name, online dot. Links to
+ *  the claw's chat (latest session resumes, or a fresh one opens). */
 export function AgentRosterItem({ agent }: { agent: Agent }) {
   return (
-    <div className="flex items-center gap-2 rounded-(--radius) px-2 py-1.5 text-sm text-foreground hover:bg-surface-warm">
+    <Link
+      href={`/claws/${agent.id}`}
+      className="flex items-center gap-2 rounded-(--radius) px-2 py-1.5 text-sm text-foreground hover:bg-surface-warm"
+    >
       <Avatar name={agent.name} accent={agent.accent} size="sm" />
       <span className="truncate">{agent.name}</span>
       {agent.status === "online" && (
@@ -14,6 +20,6 @@ export function AgentRosterItem({ agent }: { agent: Agent }) {
           className="ml-auto size-1.5 shrink-0 rounded-full bg-green-500"
         />
       )}
-    </div>
+    </Link>
   );
 }