Fix chat session management and add floating widget

- Fix session sync: events now send complete ChatSession data instead of
  partial ChatSessionSummary, ensuring proper ticket/agent info display
- Add session-ended event detection to remove closed sessions from client
- Add ChatFloatingWidget component for in-app chat experience
- Restrict endSession to ADMIN/MANAGER/AGENT roles only
- Improve polling logic to detect new and ended sessions properly

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

convex/liveChat.ts

@@ -140,7 +140,7 @@ export const startSession = mutation({
   },
 })
 
-// Agente encerra sessao de chat
+// Agente encerra sessao de chat (somente ADMIN, MANAGER ou AGENT podem encerrar)
 export const endSession = mutation({
   args: {
     sessionId: v.id("liveChatSessions"),
@@ -152,12 +152,18 @@ export const endSession = mutation({
       throw new ConvexError("Sessão não encontrada")
     }
 
-    // Verificar permissao
-    const agent = await ctx.db.get(actorId)
-    if (!agent || agent.tenantId !== session.tenantId) {
+    // Verificar permissao do usuario
+    const actor = await ctx.db.get(actorId)
+    if (!actor || actor.tenantId !== session.tenantId) {
       throw new ConvexError("Acesso negado")
     }
 
+    // Somente ADMIN, MANAGER ou AGENT podem encerrar sessoes de chat
+    const role = actor.role?.toUpperCase() ?? ""
+    if (!["ADMIN", "MANAGER", "AGENT"].includes(role)) {
+      throw new ConvexError("Apenas agentes de suporte podem encerrar sessões de chat")
+    }
+
     if (session.status !== "ACTIVE") {
       throw new ConvexError("Sessão já encerrada")
     }
@@ -179,7 +185,7 @@ export const endSession = mutation({
       payload: {
         sessionId,
         agentId: actorId,
-        agentName: agent.name,
+        agentName: actor.name,
         durationMs,
         startedAt: session.startedAt,
         endedAt: now,