Surface channel delivery failures on agent replies instead of swallowing them

The previous fix made a broken SMTP/Telegram account non-fatal — the
reply gets recorded either way now — but that also made delivery
failures completely invisible: an agent sees their reply "sent"
successfully with no indication the customer never actually received it.
Added messages.deliveryFailed, set whenever the outbound send throws, and
a warning badge on the message bubble so this is now visible instead of
silent.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Gh2UXUQUVBWroWEnn1FLFG

src/lib/tickets/delivery.ts

@@ -56,7 +56,13 @@ export async function deliverAgentMessage(params: {
   // shown in the thread) and the API route's catch-all turned it into a
   // misleading "Ticket not found". A broken mail/bot account should degrade
   // to "reply saved internally, not delivered" — never silent data loss.
+  // A ticket only ever has one channel, so at most one of the two branches
+  // below runs — this single flag is the outcome of whichever one does, and
+  // is what lets the agent tell "saved" from "the customer actually got
+  // this" in the UI (see messages.deliveryFailed).
   let emailMessageId: string | undefined;
+  let deliveryFailed = false;
+
   if (ticket.channel === "email") {
     const context = await getEmailThreadContext(params.ticketId);
     if (context) {
@@ -72,22 +78,12 @@ export async function deliverAgentMessage(params: {
         });
       } catch (err) {
         console.error(`Failed to send reply email for ticket ${params.ticketId}:`, err);
+        deliveryFailed = true;
       }
     }
-  }
-
-  const result = await recordAgentReply({
-    ticketId: params.ticketId,
-    agentId: params.agentId,
-    agentName: params.agentName,
-    body: params.body,
-    emailMessageId,
-    attachments: attachmentInput ? [attachmentInput] : undefined,
-  });
-
-  if (result.ticket.channel === "telegram") {
+  } else if (ticket.channel === "telegram") {
     const customer = await db.query.customers.findFirst({
-      where: eq(customers.id, result.ticket.customerId),
+      where: eq(customers.id, ticket.customerId),
     });
     if (customer?.telegramChatId) {
       try {
@@ -102,9 +98,20 @@ export async function deliverAgentMessage(params: {
         }
       } catch (err) {
         console.error(`Failed to deliver reply via Telegram for ticket ${params.ticketId}:`, err);
+        deliveryFailed = true;
       }
     }
   }
 
+  const result = await recordAgentReply({
+    ticketId: params.ticketId,
+    agentId: params.agentId,
+    agentName: params.agentName,
+    body: params.body,
+    emailMessageId,
+    deliveryFailed,
+    attachments: attachmentInput ? [attachmentInput] : undefined,
+  });
+
   return result;
 }