fix: improve chat flow and cleanup

Awaits sendMessage before navigating to prevent race conditions. Passes
agentId to startGeneration for correct agent resolution. Adds topic
deletion via Ctrl+Alt+Backspace shortcut. Adds date/time prefix to user
messages in LLM context. Fixes reasoning-container typo.

utils/message.ts

@@ -57,8 +57,6 @@ export const marshallMessages = (agent: Agent, messages: Readonly<MessageEntity[
     for (const message of messages) {
         switch (message.role) {
             case 'user': {
-                console.log("marshalling user message", message);
-
                 const attachments = message.attachments.map(attachment => {
                     if (attachment.file.mimeType.startsWith('image/')) {
                         return {
@@ -75,12 +73,13 @@ export const marshallMessages = (agent: Agent, messages: Readonly<MessageEntity[
                     };
                 }) as (FilePart | ImagePart)[];
 
+                let messageDate = new Date(message.createdAt);
                 marshalledMessages.push({
                     role: 'user',
                     content: [
                         {
                             type: 'text',
-                            text: message.content!
+                            text: `[${messageDate.toDateString()} ${messageDate.toLocaleTimeString()}]: ${message.content!}`
                         },
                         ...attachments,
                     ],
@@ -216,4 +215,4 @@ export const marshallMessages = (agent: Agent, messages: Readonly<MessageEntity[
     }
 
     return Ok(marshalledMessages);
-};
+};