Codex Account Switch: vanhemmat versiot ja versiohistoria

- Added gpt-5.6-sol, gpt-5.6-terra, and gpt-5.6-luna to the built-in preset model list so they appear directly in model selectors.
Improve
Fix
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- Added gpt-5.5 to the built-in preset model list so it appears directly in model selectors.
Improve
- The UI now prefers gpt-5.5 when choosing a default model with no preserved selection.
- Codex version detection now enforces a minimum request version of 0.125.0 whenever the local version is missing or older.
- Account type detection now matches keywords inside plan names, so values like prolite map to the correct account type.
Fix
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Improve
- The API proxy default model and test model list now use built-in presets instead of requesting model IDs from the upstream API.
Fix
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Added
Improve
- Returns true streaming data based on the upstream response, no longer waiting for all output to complete before returning.
- Prompts "WebView2 not installed" when the system does not have it installed.
Fix
- Token usage is included in token statistics.