feat(web): redesign Overview as the homepage with a living graph backdrop

Overview replaces Tasks as the default route: a centered new-task entry
with live fleet metrics, a scrollable/filterable task table, and an
ambient canvas rendering of the real entity graph (autonomous camera
drift + mouse parallax) behind it. Tasks sidebar entry is removed;
its status-bucketing logic moves to lib/tasks.ts for reuse.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/App.svelte

@@ -1,6 +1,5 @@
 <script lang="ts">
   import Chat from './pages/Chat.svelte'
-  import Tasks from './pages/Tasks.svelte'
   import Overview from './pages/Overview.svelte'
   import Entities from './pages/Entities.svelte'
   import Ops from './pages/Ops.svelte'
@@ -20,8 +19,6 @@
   import { Separator } from '$lib/components/ui/separator'
   import { Toaster } from '$lib/components/ui/sonner'
   import PlusIcon from '@lucide/svelte/icons/plus'
-  import ListTodoIcon from '@lucide/svelte/icons/list-todo'
-  import MessageSquareIcon from '@lucide/svelte/icons/message-square'
   import LayoutDashboardIcon from '@lucide/svelte/icons/layout-dashboard'
   import DatabaseIcon from '@lucide/svelte/icons/database'
   import PanelRightIcon from '@lucide/svelte/icons/panel-right'
@@ -31,7 +28,7 @@
   import SearchIcon from '@lucide/svelte/icons/search'
   import TrendingUpIcon from '@lucide/svelte/icons/trending-up'
 
-  let page = $state('tasks')
+  let page = $state('overview')
   let routeParam = $state('')
   let drawerOpen = $state(false)
 
@@ -40,9 +37,9 @@
 
   onMount(() => {
     function sync() {
-      const path = location.hash.slice(2) || 'tasks'
+      const path = location.hash.slice(2) || 'overview'
       const [head, ...rest] = path.split('/')
-      page = head || 'tasks'
+      page = head || 'overview'
       routeParam = rest.join('/')
     }
     sync()
@@ -114,20 +111,10 @@
     <Sidebar.Content>
       <Sidebar.Group>
         <Sidebar.Menu>
-          <Sidebar.MenuItem>
-            <Sidebar.MenuButton isActive={page === 'tasks' || page === 'chat'} onclick={() => navigate('tasks')} tooltipContent="Tasks">
-              {#snippet child({ props })}
-                <button {...props}>
-                  <ListTodoIcon />
-                  <span>Tasks</span>
-                </button>
-              {/snippet}
-            </Sidebar.MenuButton>
-          </Sidebar.MenuItem>
           {#each navItems as item}
             <Sidebar.MenuItem>
               <Sidebar.MenuButton
-                isActive={page === item.id}
+                isActive={page === item.id || (item.id === 'overview' && page === 'chat')}
                 onclick={() => navigate(item.id)}
                 tooltipContent={item.label}
               >
@@ -166,7 +153,7 @@
       <Sidebar.Trigger class="-ms-1" />
       <Separator orientation="vertical" class="mx-2 data-[orientation=vertical]:h-4" />
       {#if page === 'chat'}
-        <button type="button" class="text-sm text-muted-foreground hover:text-foreground" onclick={() => navigate('tasks')}>Tasks</button>
+        <button type="button" class="text-sm text-muted-foreground hover:text-foreground" onclick={() => navigate('overview')}>Overview</button>
         <span class="text-muted-foreground">/</span>
         <span class="text-base font-medium">Conversation</span>
       {:else}
@@ -199,8 +186,6 @@
     <main class="min-h-0 flex-1 overflow-hidden">
       {#if page === 'overview'}
         <Overview />
-      {:else if page === 'tasks'}
-        <Tasks />
       {:else if page === 'entities'}
         <Entities />
       {:else if page === 'graph'}