fix: pass assistantName to container agent instead of hardcoding 'Andy'

The container agent-runner had 'Andy' hardcoded as the sender name in
archived conversation transcripts. This ignored the configurable
ASSISTANT_NAME setting, so users who changed their assistant's name
(via .env or config) would still see 'Andy' in transcripts.

- Add assistantName field to ContainerInput interface (both host and
  container copies)
- Pass ASSISTANT_NAME from config through to container in index.ts
  and task-scheduler.ts
- Thread assistantName through createPreCompactHook and
  formatTranscriptMarkdown in the agent-runner
- Use 'AssistantNameMissing' as fallback instead of 'Andy' so a
  missing name is visible rather than silently wrong

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/index.ts

@@ -270,6 +270,7 @@ async function runAgent(
         groupFolder: group.folder,
         chatJid,
         isMain,
+        assistantName: ASSISTANT_NAME,
       },
       (proc, containerName) => queue.registerProcess(chatJid, proc, containerName, group.folder),
       wrappedOnOutput,