BUFGIX: OAuth credentials lost after in-TUI login

• When logging in to OpenAI via OAuth from within the chat (/login) while already authenticated with another provider (e.g. Anthropic) and using a non-Codex model, the freshly stored OAuth credentials were wiped from ~/.ruby_coded/config.yaml. The root cause was two UserConfig instances holding independent in-memory copies of the config; when ensure_valid_codex_model! called @user_config.set_config("model", "gpt-5.4"), the stale hash (loaded before the OAuth login) was serialized back to disk, overwriting the OAuth credentials written moments earlier by CredentialsStore. Fixed by threading a single shared UserConfig through Initializer, AuthManager, CredentialsStore and Chat::App

BUGFIX: Startup crash when stored model provider is not authenticated

The CLI no longer raises RubyLLM::ConfigurationError at startup when the model saved in ~/.ruby_coded/config.yaml belongs to a provider that has no credentials on the current machine (e.g. switching computers with only Anthropic authenticated but a GPT model stored). Instead, the app falls back to the default model of the authenticated provider and shows an in-chat system message suggesting /login or /model to adjust.

v0.2.0

Added

• ChatGPT Plus/Pro OAuth authentication: Use your ChatGPT subscription to access GPT-5.x models via the Codex backend — no API credits required
• /login command: Authenticate with providers (OpenAI, Anthropic) directly from the TUI without restarting
• In-TUI login wizard: Native multi-step login flow with OAuth and API key support, replacing the old TUI-suspend approach
• CodexBridge: Dedicated HTTP client for the ChatGPT Codex Responses API with SSE streaming, stateless conversation history, tool calls, and automatic token refresh
• Codex model catalog: Local catalog of ChatGPT-available models (gpt-5.4, gpt-5.2, gpt-5.2-codex, etc.) integrated with the /model selector
• Status bar indicator: Shows (ChatGPT) or (API) next to the model name to distinguish authentication mode
• JWT decoder: Extracts chatgpt_account_id from OAuth tokens for Codex API authentication

Changed

• OpenAI OAuth now authenticates via ChatGPT Codex backend instead of the OpenAI Platform API
• OAuth scopes expanded to openid profile email offline_access with Codex-specific auth params
• AuthManager skips OpenAI OAuth credentials for RubyLLM configuration (handled by CodexBridge)
• Default OpenAI model updated to gpt-5.4

First relase

This is the first realse (v0.1.0) of the Ruby Code gem. For this relase, I include the commits of the main branch.

Full Changelog: https://github.com/MrCesar107/ruby_code/commits/main