feat: command palette (Ctrl+K) and sidebar notification badges

- Command palette: Ctrl+K opens global task search with arrow key navigation
- Shows active/recent tasks when empty, filters on type
- Enter to open task detail page, Esc to close
- Sidebar: active task count badge (amber) and blocked count (red) on Queue nav
- Updated keyboard shortcuts modal with Ctrl+K

frontend/src/components/CommandPalette.tsx

@@ -0,0 +1,233 @@
+import { useState, useEffect, useRef, useMemo } from "react";
+import { useNavigate } from "react-router-dom";
+import { useTasks } from "../hooks/useTasks";
+import type { Task } from "../lib/types";
+
+const statusIcons: Record<string, string> = {
+  active: "⚡",
+  queued: "📋",
+  blocked: "🚫",
+  completed: "✅",
+  cancelled: "❌",
+};
+
+const priorityIcons: Record<string, string> = {
+  critical: "🔴",
+  high: "🟠",
+  medium: "🔵",
+  low: "⚪",
+};
+
+function timeAgo(dateStr: string): string {
+  const seconds = Math.floor((Date.now() - new Date(dateStr).getTime()) / 1000);
+  if (seconds < 60) return "just now";
+  const minutes = Math.floor(seconds / 60);
+  if (minutes < 60) return `${minutes}m ago`;
+  const hours = Math.floor(minutes / 60);
+  if (hours < 24) return `${hours}h ago`;
+  const days = Math.floor(hours / 24);
+  return `${days}d ago`;
+}
+
+interface CommandPaletteProps {
+  onSelectTask?: (task: Task) => void;
+}
+
+export function CommandPalette({ onSelectTask }: CommandPaletteProps) {
+  const [open, setOpen] = useState(false);
+  const [query, setQuery] = useState("");
+  const [selectedIndex, setSelectedIndex] = useState(0);
+  const { tasks } = useTasks(30000); // Slower poll for palette
+  const navigate = useNavigate();
+  const inputRef = useRef<HTMLInputElement>(null);
+  const listRef = useRef<HTMLDivElement>(null);
+
+  // Open/close with Ctrl+K
+  useEffect(() => {
+    const handleKey = (e: KeyboardEvent) => {
+      if ((e.metaKey || e.ctrlKey) && e.key === "k") {
+        e.preventDefault();
+        setOpen((prev) => {
+          if (!prev) {
+            setQuery("");
+            setSelectedIndex(0);
+          }
+          return !prev;
+        });
+      }
+      if (e.key === "Escape" && open) {
+        e.preventDefault();
+        e.stopPropagation();
+        setOpen(false);
+      }
+    };
+    window.addEventListener("keydown", handleKey, true);
+    return () => window.removeEventListener("keydown", handleKey, true);
+  }, [open]);
+
+  // Focus input when opened
+  useEffect(() => {
+    if (open) {
+      setTimeout(() => inputRef.current?.focus(), 50);
+    }
+  }, [open]);
+
+  const results = useMemo(() => {
+    if (!query.trim()) {
+      // Show active and recent tasks when no query
+      return tasks
+        .filter((t) => t.status === "active" || t.status === "queued" || t.status === "blocked")
+        .slice(0, 10);
+    }
+    const q = query.toLowerCase();
+    return tasks
+      .filter(
+        (t) =>
+          t.title.toLowerCase().includes(q) ||
+          (t.description && t.description.toLowerCase().includes(q)) ||
+          (t.taskNumber && `hq-${t.taskNumber}`.includes(q)) ||
+          (t.assigneeName && t.assigneeName.toLowerCase().includes(q)) ||
+          (t.tags && t.tags.some((tag) => tag.toLowerCase().includes(q)))
+      )
+      .slice(0, 15);
+  }, [tasks, query]);
+
+  // Keep selected index in bounds
+  useEffect(() => {
+    setSelectedIndex(0);
+  }, [query]);
+
+  const handleSelect = (task: Task) => {
+    setOpen(false);
+    if (onSelectTask) {
+      onSelectTask(task);
+    } else {
+      navigate(`/task/HQ-${task.taskNumber}`);
+    }
+  };
+
+  const handleKeyDown = (e: React.KeyboardEvent) => {
+    if (e.key === "ArrowDown") {
+      e.preventDefault();
+      setSelectedIndex((prev) => Math.min(prev + 1, results.length - 1));
+    } else if (e.key === "ArrowUp") {
+      e.preventDefault();
+      setSelectedIndex((prev) => Math.max(prev - 1, 0));
+    } else if (e.key === "Enter" && results[selectedIndex]) {
+      e.preventDefault();
+      handleSelect(results[selectedIndex]);
+    }
+  };
+
+  // Scroll selected item into view
+  useEffect(() => {
+    if (!listRef.current) return;
+    const el = listRef.current.children[selectedIndex] as HTMLElement;
+    if (el) el.scrollIntoView({ block: "nearest" });
+  }, [selectedIndex]);
+
+  if (!open) return null;
+
+  return (
+    <>
+      <div className="fixed inset-0 bg-black/40 backdrop-blur-sm z-[70]" onClick={() => setOpen(false)} />
+      <div className="fixed inset-0 flex items-start justify-center z-[71] pt-[15vh] px-4">
+        <div className="bg-white dark:bg-gray-900 rounded-2xl shadow-2xl border border-gray-200 dark:border-gray-700 w-full max-w-lg overflow-hidden">
+          {/* Search input */}
+          <div className="flex items-center gap-3 px-4 py-3 border-b border-gray-100 dark:border-gray-800">
+            <svg className="w-5 h-5 text-gray-400 dark:text-gray-500 shrink-0" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M21 21l-6-6m2-5a7 7 0 11-14 0 7 7 0 0114 0z" />
+            </svg>
+            <input
+              ref={inputRef}
+              type="text"
+              value={query}
+              onChange={(e) => setQuery(e.target.value)}
+              onKeyDown={handleKeyDown}
+              placeholder="Search tasks... (type to filter)"
+              className="flex-1 bg-transparent border-none outline-none text-gray-900 dark:text-gray-100 placeholder:text-gray-400 dark:placeholder:text-gray-500 text-sm"
+            />
+            <kbd className="px-1.5 py-0.5 text-[10px] font-mono text-gray-400 dark:text-gray-500 bg-gray-100 dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded">
+              Esc
+            </kbd>
+          </div>
+
+          {/* Results */}
+          <div ref={listRef} className="max-h-[50vh] overflow-y-auto py-2">
+            {results.length === 0 ? (
+              <div className="text-center py-8 text-sm text-gray-400 dark:text-gray-500">
+                {query ? "No tasks found" : "No active tasks"}
+              </div>
+            ) : (
+              results.map((task, i) => (
+                <button
+                  key={task.id}
+                  onClick={() => handleSelect(task)}
+                  onMouseEnter={() => setSelectedIndex(i)}
+                  className={`w-full text-left px-4 py-2.5 flex items-start gap-3 transition ${
+                    i === selectedIndex
+                      ? "bg-amber-50 dark:bg-amber-900/20"
+                      : "hover:bg-gray-50 dark:hover:bg-gray-800"
+                  }`}
+                >
+                  <span className="text-sm shrink-0 mt-0.5">{statusIcons[task.status] || "📋"}</span>
+                  <div className="flex-1 min-w-0">
+                    <div className="flex items-center gap-2">
+                      <span className="text-xs font-mono font-bold text-gray-400 dark:text-gray-500">
+                        HQ-{task.taskNumber}
+                      </span>
+                      <span className="text-[10px]">{priorityIcons[task.priority]}</span>
+                      {task.tags?.slice(0, 2).map((tag) => (
+                        <span key={tag} className="text-[10px] text-violet-500 dark:text-violet-400">
+                          #{tag}
+                        </span>
+                      ))}
+                    </div>
+                    <p className={`text-sm truncate ${
+                      i === selectedIndex
+                        ? "text-amber-900 dark:text-amber-200 font-medium"
+                        : "text-gray-700 dark:text-gray-300"
+                    }`}>
+                      {task.title}
+                    </p>
+                    <div className="flex items-center gap-2 mt-0.5">
+                      {task.assigneeName && (
+                        <span className="text-[10px] text-gray-400 dark:text-gray-500">
+                          👤 {task.assigneeName}
+                        </span>
+                      )}
+                      <span className="text-[10px] text-gray-400 dark:text-gray-500">
+                        {timeAgo(task.updatedAt)}
+                      </span>
+                    </div>
+                  </div>
+                  {i === selectedIndex && (
+                    <span className="text-[10px] text-gray-400 dark:text-gray-500 mt-1 shrink-0">
+                      ↵ Open
+                    </span>
+                  )}
+                </button>
+              ))
+            )}
+          </div>
+
+          {/* Footer */}
+          <div className="px-4 py-2.5 border-t border-gray-100 dark:border-gray-800 flex items-center gap-4 text-[10px] text-gray-400 dark:text-gray-500">
+            <span className="flex items-center gap-1">
+              <kbd className="px-1 py-0.5 bg-gray-100 dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded font-mono">↑↓</kbd>
+              Navigate
+            </span>
+            <span className="flex items-center gap-1">
+              <kbd className="px-1 py-0.5 bg-gray-100 dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded font-mono">↵</kbd>
+              Open
+            </span>
+            <span className="flex items-center gap-1">
+              <kbd className="px-1 py-0.5 bg-gray-100 dark:bg-gray-800 border border-gray-200 dark:border-gray-700 rounded font-mono">Esc</kbd>
+              Close
+            </span>
+          </div>
+        </div>
+      </div>
+    </>
+  );
+}

frontend/src/components/DashboardLayout.tsx

@@ -1,23 +1,29 @@
-import { useState } from "react";
+import { useState, useMemo } from "react";
 import { NavLink, Outlet } from "react-router-dom";
 import { useCurrentUser } from "../hooks/useCurrentUser";
+import { useTasks } from "../hooks/useTasks";
 import { useTheme } from "../hooks/useTheme";
 import { KeyboardShortcutsModal } from "./KeyboardShortcutsModal";
+import { CommandPalette } from "./CommandPalette";
 import { signOut } from "../lib/auth-client";
 
 const navItems = [
-  { to: "/", label: "Dashboard", icon: "🔨" },
+  { to: "/", label: "Dashboard", icon: "🔨", badgeKey: null },
-  { to: "/queue", label: "Queue", icon: "📋" },
+  { to: "/queue", label: "Queue", icon: "📋", badgeKey: "queue" },
-  { to: "/projects", label: "Projects", icon: "📁" },
+  { to: "/projects", label: "Projects", icon: "📁", badgeKey: null },
-  { to: "/activity", label: "Activity", icon: "📝" },
+  { to: "/activity", label: "Activity", icon: "📝", badgeKey: null },
-  { to: "/chat", label: "Chat", icon: "💬" },
+  { to: "/chat", label: "Chat", icon: "💬", badgeKey: null },
-];
+] as const;
 
 export function DashboardLayout() {
   const { user, isAdmin } = useCurrentUser();
+  const { tasks } = useTasks(15000);
   const { theme, setTheme } = useTheme();
   const [sidebarOpen, setSidebarOpen] = useState(false);
 
+  const activeTasks = useMemo(() => tasks.filter((t) => t.status === "active").length, [tasks]);
+  const blockedTasks = useMemo(() => tasks.filter((t) => t.status === "blocked").length, [tasks]);
+
   const cycleTheme = () => {
     const next = theme === "light" ? "dark" : theme === "dark" ? "system" : "light";
     setTheme(next);
@@ -97,7 +103,9 @@ export function DashboardLayout() {
 
         {/* Navigation */}
         <nav className="flex-1 px-3 py-4 space-y-1">
-          {navItems.map((item) => (
+          {navItems.map((item) => {
+            const badge = item.badgeKey === "queue" && activeTasks > 0 ? activeTasks : 0;
+            return (
               <NavLink
                 key={item.to}
                 to={item.to}
@@ -112,9 +120,20 @@ export function DashboardLayout() {
                 }
               >
                 <span className="text-lg">{item.icon}</span>
-              {item.label}
+                <span className="flex-1">{item.label}</span>
+                {badge > 0 && (
+                  <span className="text-[10px] font-bold bg-amber-500 text-white px-1.5 py-0.5 rounded-full min-w-[18px] text-center leading-none">
+                    {badge}
+                  </span>
+                )}
+                {item.badgeKey === "queue" && blockedTasks > 0 && (
+                  <span className="text-[10px] font-bold bg-red-500 text-white px-1.5 py-0.5 rounded-full min-w-[18px] text-center leading-none">
+                    {blockedTasks}
+                  </span>
+                )}
               </NavLink>
-          ))}
+            );
+          })}
           {isAdmin && (
             <NavLink
               to="/admin"
@@ -173,6 +192,7 @@ export function DashboardLayout() {
       </main>
 
       <KeyboardShortcutsModal />
+      <CommandPalette />
     </div>
   );
 }

frontend/src/components/KeyboardShortcutsModal.tsx

@@ -1,6 +1,7 @@
 import { useEffect, useState } from "react";
 
 const shortcuts = [
+  { keys: ["Ctrl", "K"], action: "Open command palette", context: "Global" },
   { keys: ["Ctrl", "N"], action: "Create new task", context: "Queue" },
   { keys: ["Esc"], action: "Close panel / Cancel edit", context: "Global" },
   { keys: ["?"], action: "Show keyboard shortcuts", context: "Global" },