[Bug] OpenCode model pickers include disabled models #1078

Description

Models configured with providers.<id>.models.<id>.disabled: true still appear in Codeg's OpenCode model pickers, including the settings page and chat window.

The settings page combines configured and catalog models without checking the disabled flag. Its config-only fallback can also reintroduce models from providers denied by policy when no other options remain.

Steps to reproduce

1. Configure an OpenCode provider with a model marked disabled: true.
2. Open a default-model picker in Codeg's OpenCode settings.
3. Start an OpenCode session and open the chat model picker.
4. Observe that the disabled model is still offered.

Expected behavior

Disabled models should be excluded from both settings and chat model pickers.

Settings pickers should apply the filter to configured and catalog models, including before the catalog loads. Providers denied by policy should remain excluded when no options remain.

Chat model options should exclude disabled models and their variants consistently across session initialization and subsequent updates.