batch4.1-5.1: dedup audit, archive 400 fix, sidebar Delete, landing-page enrichment, auto-name tool-call fix

- Fastify global empty-JSON-body parser fixes archive/unarchive/stop 400s
- Removed redundant local sessionEvents.emit at all 5+2 sites with server-side WS publishers; added dedupe guards in useSidebar/Workspace/Project handlers
- Sidebar session right-click adds Delete (destructive) with confirm Dialog
- Session.tsx navigates away on session_deleted/session_archived for the active session
- SessionLandingPage chat rows show message_count, effective_context_tokens, last_message_preview via LATERAL joins on GET /api/sessions/:id/chats
- Workspace.tsx pane drag-to-reorder using native HTML5 events (no new deps)
- CompactCard: Copy toast, Send-to-chat with target chat name, empty-state in share popover, Re-run button
- auto_name.ts: filter count gate and assistant-fetch by content <> '' so tool-call assistant rows don't trip the once-and-only-once guard
- Adds CLAUDE.md and apps/web/src/lib/format.ts

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/src/components/SessionLandingPage.tsx

@@ -3,6 +3,7 @@ import { MessageSquare, Send, ChevronDown, ChevronRight } from 'lucide-react';
 import type { Chat } from '@/api/types';
 import { Button } from '@/components/ui/button';
 import { Textarea } from '@/components/ui/textarea';
+import { formatTokens } from '@/lib/format';
 
 interface Props {
   sessionId: string;
@@ -27,6 +28,51 @@ function relTime(iso: string): string {
   return `${day}d ago`;
 }
 
+function ChatRow({
+  chat,
+  onClick,
+  dimmed,
+  trailing,
+}: {
+  chat: Chat;
+  onClick: () => void;
+  dimmed?: boolean;
+  trailing?: string;
+}) {
+  const meta: string[] = [relTime(chat.updated_at)];
+  if (chat.message_count !== undefined && chat.message_count > 0) {
+    meta.push(`${chat.message_count} msg`);
+  }
+  const tokens = formatTokens(chat.effective_context_tokens);
+  if (tokens) meta.push(tokens);
+  const preview = chat.last_message_preview;
+  return (
+    <button
+      type="button"
+      onClick={onClick}
+      className="w-full flex flex-col gap-0.5 px-3 py-2 hover:bg-muted/50 text-left"
+    >
+      <div className="flex items-center gap-2 min-w-0">
+        <MessageSquare className={`size-3.5 shrink-0 ${dimmed ? 'opacity-40' : 'opacity-70'}`} />
+        <span className={`truncate text-sm flex-1 ${dimmed ? 'text-muted-foreground' : ''}`}>
+          {chat.name ?? 'New chat'}
+        </span>
+        {trailing && (
+          <span className="text-xs text-muted-foreground shrink-0">{trailing}</span>
+        )}
+      </div>
+      <div className="ml-5 text-xs text-muted-foreground tabular-nums">
+        {meta.join(' · ')}
+      </div>
+      {preview && (
+        <div className="ml-5 text-xs italic text-muted-foreground truncate">
+          {preview}
+        </div>
+      )}
+    </button>
+  );
+}
+
 export function SessionLandingPage({
   chats,
   onOpenChat,
@@ -50,6 +96,10 @@ export function SessionLandingPage({
     setComposerValue('');
   }
 
+  // TODO: Landing page chat counts are a snapshot at mount. New messages in
+  // visible chats won't update the per-row stats until next mount/navigation.
+  // Wiring WS reactivity through here is deferred (rare use case: user is in
+  // a pane when messages stream, not on the landing page).
   return (
     <div className="flex flex-col h-full min-h-0">
       <div className="flex-1 overflow-y-auto px-6 py-4 space-y-6">
@@ -60,19 +110,7 @@ export function SessionLandingPage({
             <ul className="divide-y rounded-md border">
               {openChats.map((chat) => (
                 <li key={chat.id}>
-                  <button
-                    type="button"
-                    onClick={() => onOpenChat(chat.id)}
-                    className="w-full flex items-center gap-2 px-3 py-2 hover:bg-muted/50 text-left"
-                  >
-                    <MessageSquare className="size-3.5 opacity-70 shrink-0" />
-                    <span className="truncate text-sm flex-1">
-                      {chat.name ?? 'New chat'}
-                    </span>
-                    <span className="text-xs text-muted-foreground shrink-0 tabular-nums">
-                      {relTime(chat.updated_at)}
-                    </span>
-                  </button>
+                  <ChatRow chat={chat} onClick={() => onOpenChat(chat.id)} />
                 </li>
               ))}
             </ul>
@@ -94,19 +132,12 @@ export function SessionLandingPage({
               <ul className="divide-y rounded-md border">
                 {closedChats.map((chat) => (
                   <li key={chat.id}>
-                    <button
-                      type="button"
+                    <ChatRow
+                      chat={chat}
                       onClick={() => void onReopenChat(chat.id)}
-                      className="w-full flex items-center gap-2 px-3 py-2 hover:bg-muted/50 text-left"
-                    >
-                      <MessageSquare className="size-3.5 opacity-40 shrink-0" />
-                      <span className="truncate text-sm flex-1 text-muted-foreground">
-                        {chat.name ?? 'New chat'}
-                      </span>
-                      <span className="text-xs text-muted-foreground shrink-0">
-                        Reopen
-                      </span>
-                    </button>
+                      dimmed
+                      trailing="Reopen"
+                    />
                   </li>
                 ))}
               </ul>