[Bug]: Missing `codex` blocks Claude Code selection and limits model picker to Codex models

[domainus]

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Install Claude Code
2. Do NOT have Codex in PATH or installed
3. Open T3Code
4. Go to model picker

Expected behavior

T3 Code should not depend on codex to make assistant features usable.

If Claude Code is installed and available, the app should allow selecting and using Claude Code even when codex is missing.

Provider/model availability should be resolved independently:

• missing codex should only disable Codex
• missing Claude Code should only disable Claude Code

Actual behavior

codex missing appears to gate the whole provider/model flow:

• Codex errors are shown
• only Codex models are available in the picker
• Claude Code cannot be selected

Impact

Blocks work completely

Version or commit

0.0.13

Environment

Bazzite-nvidia-open:stable

Related

I could not find an exact matching open issue, but this issue seems related:

#1221