feat: top navbar (Build|Market|Assist) + persistent Assist chat in shell

- New top navbar in ProjectShell: logo + project name | Build | Market |
  Assist tabs | user avatar — replaces the left icon sidebar for project pages
- CooChat extracted to components/layout/coo-chat.tsx and moved into the
  shell so it persists across Build/Market/Assist route changes
- Build page inner layout simplified: inner nav (200px) + file viewer,
  no longer owns the chat column
- Layout: [top nav 48px] / [Assist chat 320px | content flex]

Made-with: Cursor

app/[workspace]/project/[projectId]/build/page.tsx

@@ -812,181 +812,6 @@ function TerminalPanel({ appName }: { appName: string }) {
   );
 }
 
-// ── COO / Assist chat — persistent left-side advisor ─────────────────────────
-
-interface CooMessage {
-  id: string;
-  role: "user" | "assistant";
-  content: string;
-  streaming?: boolean;
-}
-
-const WELCOME: CooMessage = {
-  id: "welcome",
-  role: "assistant",
-  content: "Hi. I'm your product COO — I know your codebase, your goals, and what's been built. What do you need?",
-};
-
-function CooChat({ projectId, projectName }: { projectId: string; projectName: string }) {
-  const [messages, setMessages] = useState<CooMessage[]>([WELCOME]);
-  const [input, setInput] = useState("");
-  const [loading, setLoading] = useState(false);
-  const bottomRef = useRef<HTMLDivElement>(null);
-  const textareaRef = useRef<HTMLTextAreaElement>(null);
-
-  useEffect(() => {
-    bottomRef.current?.scrollIntoView({ behavior: "smooth" });
-  }, [messages]);
-
-  const send = async () => {
-    const text = input.trim();
-    if (!text || loading) return;
-    setInput("");
-
-    const userMsg: CooMessage = { id: Date.now().toString(), role: "user", content: text };
-    const assistantId = (Date.now() + 1).toString();
-    const assistantMsg: CooMessage = { id: assistantId, role: "assistant", content: "", streaming: true };
-
-    setMessages(prev => [...prev, userMsg, assistantMsg]);
-    setLoading(true);
-
-    // Build history for the API (exclude welcome message, exclude the new blank assistant placeholder)
-    const history = messages
-      .filter(m => m.id !== "welcome" && m.content)
-      .map(m => ({ role: m.role === "assistant" ? "model" as const : "user" as const, content: m.content }));
-
-    try {
-      const res = await fetch(`/api/projects/${projectId}/advisor`, {
-        method: "POST",
-        headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ message: text, history }),
-      });
-
-      if (!res.ok || !res.body) {
-        setMessages(prev => prev.map(m => m.id === assistantId
-          ? { ...m, content: "Something went wrong. Please try again.", streaming: false }
-          : m));
-        return;
-      }
-
-      const reader = res.body.getReader();
-      const decoder = new TextDecoder();
-
-      while (true) {
-        const { done, value } = await reader.read();
-        if (done) break;
-        const chunk = decoder.decode(value, { stream: true });
-        setMessages(prev => prev.map(m => m.id === assistantId
-          ? { ...m, content: m.content + chunk }
-          : m));
-      }
-
-      setMessages(prev => prev.map(m => m.id === assistantId ? { ...m, streaming: false } : m));
-    } catch {
-      setMessages(prev => prev.map(m => m.id === assistantId
-        ? { ...m, content: "Connection error. Please try again.", streaming: false }
-        : m));
-    } finally {
-      setLoading(false);
-      textareaRef.current?.focus();
-    }
-  };
-
-  return (
-    <div style={{ flex: 1, display: "flex", flexDirection: "column", overflow: "hidden" }}>
-      {/* Messages */}
-      <div style={{ flex: 1, overflow: "auto", padding: "16px 16px 8px", display: "flex", flexDirection: "column", gap: 14 }}>
-        {messages.map(msg => (
-          <div key={msg.id} style={{
-            display: "flex",
-            flexDirection: msg.role === "user" ? "row-reverse" : "row",
-            alignItems: "flex-end", gap: 8,
-          }}>
-            {msg.role === "assistant" && (
-              <span style={{ width: 22, height: 22, borderRadius: 6, background: "#1a1a1a", display: "flex", alignItems: "center", justifyContent: "center", fontSize: "0.58rem", color: "#fff", flexShrink: 0 }}>◈</span>
-            )}
-            <div style={{
-              maxWidth: "82%",
-              padding: msg.role === "user" ? "8px 12px" : "0",
-              background: msg.role === "user" ? "#f0ece4" : "transparent",
-              borderRadius: msg.role === "user" ? 12 : 0,
-              fontSize: "0.8rem",
-              color: "#1a1a1a",
-              fontFamily: "Outfit, sans-serif",
-              lineHeight: 1.6,
-              whiteSpace: "pre-wrap",
-              wordBreak: "break-word",
-            }}>
-              {msg.content || (msg.streaming ? "" : "")}
-              {msg.streaming && msg.content === "" && (
-                <span style={{ display: "inline-flex", gap: 3, alignItems: "center" }}>
-                  {[0, 1, 2].map(i => (
-                    <span key={i} style={{
-                      width: 4, height: 4, borderRadius: "50%", background: "#b5b0a6", display: "inline-block",
-                      animation: `bounce 1.2s ${i * 0.2}s ease-in-out infinite`,
-                    }} />
-                  ))}
-                </span>
-              )}
-              {msg.streaming && msg.content !== "" && (
-                <span style={{ display: "inline-block", width: 2, height: "0.9em", background: "#1a1a1a", marginLeft: 1, verticalAlign: "text-bottom", animation: "blink 1s step-end infinite" }} />
-              )}
-            </div>
-          </div>
-        ))}
-        <div ref={bottomRef} />
-      </div>
-
-      {/* Input */}
-      <div style={{ flexShrink: 0, borderTop: "1px solid #e8e4dc", padding: "10px 12px", background: "#fff" }}>
-        <div style={{ display: "flex", gap: 8, alignItems: "flex-end" }}>
-          <textarea
-            ref={textareaRef}
-            value={input}
-            onChange={e => setInput(e.target.value)}
-            onKeyDown={e => { if (e.key === "Enter" && !e.shiftKey) { e.preventDefault(); send(); } }}
-            placeholder={loading ? "Thinking…" : "Ask anything…"}
-            disabled={loading}
-            rows={2}
-            style={{
-              flex: 1, resize: "none", border: "1px solid #e8e4dc", borderRadius: 10,
-              padding: "8px 11px", fontSize: "0.8rem", fontFamily: "Outfit, sans-serif",
-              color: "#1a1a1a", outline: "none", background: loading ? "#faf8f5" : "#faf8f5",
-              lineHeight: 1.5,
-            }}
-          />
-          <button
-            onClick={send}
-            disabled={!input.trim() || loading}
-            style={{
-              width: 34, height: 34, flexShrink: 0, border: "none", borderRadius: 9,
-              background: input.trim() && !loading ? "#1a1a1a" : "#e8e4dc",
-              color: input.trim() && !loading ? "#fff" : "#b5b0a6",
-              cursor: input.trim() && !loading ? "pointer" : "default",
-              display: "flex", alignItems: "center", justifyContent: "center",
-              fontSize: "0.85rem", transition: "background 0.15s",
-            }}
-          >↑</button>
-        </div>
-        <div style={{ fontSize: "0.62rem", color: "#b5b0a6", marginTop: 5, fontFamily: "Outfit, sans-serif" }}>
-          ↵ to send · Shift+↵ new line
-        </div>
-      </div>
-
-      <style>{`
-        @keyframes bounce {
-          0%, 60%, 100% { transform: translateY(0); }
-          30% { transform: translateY(-4px); }
-        }
-        @keyframes blink {
-          0%, 100% { opacity: 1; }
-          50% { opacity: 0; }
-        }
-      `}</style>
-    </div>
-  );
-}
-
 // ── File tree (lives in sidebar B) ───────────────────────────────────────────
 
 function FileTree({ projectId, rootPath, selectedPath, onSelectFile }: {
@@ -1110,7 +935,6 @@ function BuildHubInner() {
   const [apps, setApps] = useState<AppEntry[]>([]);
   const [surfaces, setSurfaces] = useState<SurfaceEntry[]>([]);
   const [activeSurfaceId, setActiveSurfaceId] = useState<string>(activeSurfaceParam);
-  const [projectName, setProjectName] = useState<string>("");
 
   // File viewer state — shared between inner nav (tree) and viewer panel
   const [selectedFilePath, setSelectedFilePath] = useState<string | null>(null);
@@ -1121,10 +945,7 @@ function BuildHubInner() {
   useEffect(() => {
     fetch(`/api/projects/${projectId}/apps`)
       .then(r => r.json())
-      .then(d => {
-        setApps(d.apps ?? []);
-        if (d.projectName) setProjectName(d.projectName);
-      }).catch(() => {});
+      .then(d => { setApps(d.apps ?? []); }).catch(() => {});
     fetch(`/api/projects/${projectId}/design-surfaces`).then(r => r.json()).then(d => {
       const ids: string[] = d.surfaces ?? [];
       const themes: Record<string, string> = d.surfaceThemes ?? {};
@@ -1162,24 +983,7 @@ function BuildHubInner() {
   return (
     <div style={{ display: "flex", height: "100%", fontFamily: "Outfit, sans-serif", overflow: "hidden" }}>
 
-      {/* ── Left: COO / Assist persistent chat ── */}
-      <div style={{ width: 340, flexShrink: 0, borderRight: "1px solid #e8e4dc", background: "#fff", display: "flex", flexDirection: "column", overflow: "hidden" }}>
-
-        {/* Advisor header */}
-        <div style={{ height: 48, flexShrink: 0, display: "flex", alignItems: "center", padding: "0 14px", borderBottom: "1px solid #e8e4dc", gap: 9, background: "#faf8f5" }}>
-          <span style={{ width: 26, height: 26, borderRadius: 7, background: "#1a1a1a", display: "flex", alignItems: "center", justifyContent: "center", fontSize: "0.68rem", color: "#fff", flexShrink: 0 }}>◈</span>
-          <div style={{ flex: 1, minWidth: 0 }}>
-            <div style={{ fontSize: "0.78rem", fontWeight: 600, color: "#1a1a1a", fontFamily: "Outfit, sans-serif", overflow: "hidden", textOverflow: "ellipsis", whiteSpace: "nowrap" }}>
-              {projectName || workspace}
-            </div>
-            <div style={{ fontSize: "0.6rem", color: "#a09a90", fontFamily: "Outfit, sans-serif", letterSpacing: "0.04em" }}>Assist · Your product COO</div>
-          </div>
-        </div>
-
-        <CooChat projectId={projectId} projectName={projectName || workspace} />
-      </div>
-
-      {/* ── Right: Build content ── */}
+      {/* ── Build content ── */}
       <div style={{ flex: 1, display: "flex", overflow: "hidden", minWidth: 0 }}>
 
         {/* Inner nav — Build section switcher + contextual items */}