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/server/src/routes/chats.ts

@@ -26,11 +26,37 @@ export function registerChatRoutes(
         reply.code(404);
         return { error: 'session not found' };
       }
+      // Enriched list: computed per-chat fields via LATERAL joins.
+      // `effective_context_tokens` = ctx_used (prompt tokens) on the most
+      // recent complete assistant message — represents the current context
+      // window consumption post-compact.
       const rows = await sql<Chat[]>`
-        SELECT id, session_id, name, status, created_at, updated_at
-        FROM chats
-        WHERE session_id = ${req.params.id}
-        ORDER BY updated_at DESC
+        SELECT
+          c.id, c.session_id, c.name, c.status, c.created_at, c.updated_at,
+          COALESCE(mc.cnt, 0)::int AS message_count,
+          lp.preview AS last_message_preview,
+          ec.tokens AS effective_context_tokens
+        FROM chats c
+        LEFT JOIN LATERAL (
+          SELECT COUNT(*) AS cnt FROM messages WHERE chat_id = c.id
+        ) mc ON TRUE
+        LEFT JOIN LATERAL (
+          SELECT LEFT(BTRIM(REGEXP_REPLACE(content, E'[\\n\\r]+', ' ', 'g')), 80) AS preview
+          FROM messages
+          WHERE chat_id = c.id AND kind = 'message' AND content <> ''
+          ORDER BY created_at DESC
+          LIMIT 1
+        ) lp ON TRUE
+        LEFT JOIN LATERAL (
+          SELECT ctx_used AS tokens
+          FROM messages
+          WHERE chat_id = c.id AND kind = 'message' AND role = 'assistant'
+            AND status = 'complete' AND ctx_used IS NOT NULL
+          ORDER BY created_at DESC
+          LIMIT 1
+        ) ec ON TRUE
+        WHERE c.session_id = ${req.params.id}
+        ORDER BY c.updated_at DESC
       `;
       return rows;
     }