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/hooks/useSidebar.ts

@@ -52,6 +52,7 @@ function load(): Promise<void> {
 function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').SessionEvent): SidebarResponse {
   switch (event.type) {
     case 'project_created': {
+      if (prev.projects.some((p) => p.id === event.project.id)) return prev;
       const fresh: SidebarProject = {
         id: event.project.id,
         name: event.project.name,
@@ -69,6 +70,7 @@ function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').Sess
       let changed = false;
       const projects = prev.projects.map((p) => {
         if (p.id !== event.project_id) return p;
+        if (p.recent_sessions.some((s) => s.id === event.session.id)) return p;
         changed = true;
         const fresh: SidebarSession = {
           id: event.session.id,
@@ -89,8 +91,10 @@ function applyEvent(prev: SidebarResponse, event: import('./sessionEvents').Sess
       let changed = false;
       const projects = prev.projects.map((p) => {
         if (p.id !== event.project_id) return p;
-        changed = true;
         const recent = p.recent_sessions.filter((s) => s.id !== event.session_id);
+        const wasPresent = recent.length !== p.recent_sessions.length;
+        if (!wasPresent) return p;
+        changed = true;
         return {
           ...p,
           recent_sessions: recent,