chore(models): update default client version and user agent, revise GPT-5.6 Sol configuration

- Incremented `defaultClientVersion` and `defaultCodexUserAgent` to `0.144.1`.
- Replaced GPT-5.5 with GPT-5.6 Sol in model registry, updating metadata including context window length, reasoning levels, and description.
- Enhanced model metadata with adjusted parameters, reasoning format, and new effort levels.

cmd/fetch_codex_models/main.go

@@ -42,8 +42,8 @@ import (
 const (
 	codexModelsBaseURL       = "https://chatgpt.com/backend-api/codex"
 	codexModelsPath          = "/models"
-	defaultClientVersion     = "0.144.0"
-	defaultCodexUserAgent    = "codex_cli_rs/0.144.0 (Mac OS 26.3.1; arm64) iTerm.app/3.6.9"
+	defaultClientVersion     = "0.144.1"
+	defaultCodexUserAgent    = "codex_cli_rs/0.144.1 (Mac OS 26.3.1; arm64) iTerm.app/3.6.9"
 	defaultCodexOriginator   = "codex_cli_rs"
 	accessTokenRefreshLeeway = 30 * time.Second
 )