Model selector ignores light mode and unreadable "More models" button #355

Description

When the Web UI is in light mode, the model selection sheet (opened from the model name in the chat) is still rendered with a dark background. Below the model list, the "More models" button sits on a light background with white/near-white text, so it's barely readable.

Steps to reproduce

1. Set the Web UI to light mode
2. Open a session and tap the current model name to open the model selector

Expected behavior

• The model selector sheet follows the active theme (light background in light mode)
• "More models" has enough contrast to be readable

Environment

• OpenCode Manager version: v0.17.5
• Deployment: Podman, accessed over LAN
• Device: iPhone, iOS 27.0
• Browser: Brave for iOS, Version 1.94 (122); Same behavior on Safari for iOS

Screenshot