Exort v0.4.1

• OpenCode v2: New installations automatically set up OpenCode 2.0.14, resolving the outdated-runtime error affecting free-tier models.
• Built-in OpenCode updates: Get notified when a newer stable version is available. Clicking Check for updates in Settings → Requirements checks and installs available updates.
• Updates without restarting Exort: Runtime updates wait until the agent is idle before activating.
• Chat attachments: Drag and drop files, paste images from your clipboard, and preview image attachments.
• Improved chat reliability: Better recovery from disconnected streams, with fewer duplicate messages and stuck streaming indicators.
• Safer upgrades: Runtime data is backed up before migration, preserving chat history, provider connections, and model preferences.