[UI] Old UI on new event loop

In preparation for the new event loop, which is to be written decoupled from the visual layer, we need to preserve the same UX while the new UI is underway.

There are the following todos to be completed in order for this to be achieved:
- [ ] UI managed input (https://github.com/aws/amazon-q-developer-cli/pull/3254)
- [ ] Slash command (autocompletion + structured event egress)
- [ ] Skim integration
- [ ] MCP prompts (autocompletion + structured event egress)
- [ ] History integration
- [ ] Image pasting integration (Pasting of path + pasting of image from clipboard)

Make sure to comment on this issue (with a draft PR if applicable) if you are working on any of these.

Inizia esaminando la checklist dell’issue e il lavoro esistente sugli input gestiti dalla UI in PR #3254. Completa le integrazioni rimanenti di slash-command, Skim, MCP prompt, history e image-pasting nella CLI UI del repository, preservando la UX esistente per il nuovo event loop. Il lavoro è completato quando l’elemento applicabile della checklist è implementato e documentato con un commento o una draft PR.

Scritto dal modello di indicizzazione a partire dal testo della issue.