feat: Complete LLMX v0.1.0 - Rebrand from Codex with LiteLLM Integration

This release represents a comprehensive transformation of the codebase from Codex to LLMX,
enhanced with LiteLLM integration to support 100+ LLM providers through a unified API.

## Major Changes

### Phase 1: Repository & Infrastructure Setup
- Established new repository structure and branching strategy
- Created comprehensive project documentation (CLAUDE.md, LITELLM-SETUP.md)
- Set up development environment and tooling configuration

### Phase 2: Rust Workspace Transformation
- Renamed all Rust crates from `codex-*` to `llmx-*` (30+ crates)
- Updated package names, binary names, and workspace members
- Renamed core modules: codex.rs → llmx.rs, codex_delegate.rs → llmx_delegate.rs
- Updated all internal references, imports, and type names
- Renamed directories: codex-rs/ → llmx-rs/, codex-backend-openapi-models/ → llmx-backend-openapi-models/
- Fixed all Rust compilation errors after mass rename

### Phase 3: LiteLLM Integration
- Integrated LiteLLM for multi-provider LLM support (Anthropic, OpenAI, Azure, Google AI, AWS Bedrock, etc.)
- Implemented OpenAI-compatible Chat Completions API support
- Added model family detection and provider-specific handling
- Updated authentication to support LiteLLM API keys
- Renamed environment variables: OPENAI_BASE_URL → LLMX_BASE_URL
- Added LLMX_API_KEY for unified authentication
- Enhanced error handling for Chat Completions API responses
- Implemented fallback mechanisms between Responses API and Chat Completions API

### Phase 4: TypeScript/Node.js Components
- Renamed npm package: @codex/codex-cli → @valknar/llmx
- Updated TypeScript SDK to use new LLMX APIs and endpoints
- Fixed all TypeScript compilation and linting errors
- Updated SDK tests to support both API backends
- Enhanced mock server to handle multiple API formats
- Updated build scripts for cross-platform packaging

### Phase 5: Configuration & Documentation
- Updated all configuration files to use LLMX naming
- Rewrote README and documentation for LLMX branding
- Updated config paths: ~/.codex/ → ~/.llmx/
- Added comprehensive LiteLLM setup guide
- Updated all user-facing strings and help text
- Created release plan and migration documentation

### Phase 6: Testing & Validation
- Fixed all Rust tests for new naming scheme
- Updated snapshot tests in TUI (36 frame files)
- Fixed authentication storage tests
- Updated Chat Completions payload and SSE tests
- Fixed SDK tests for new API endpoints
- Ensured compatibility with Claude Sonnet 4.5 model
- Fixed test environment variables (LLMX_API_KEY, LLMX_BASE_URL)

### Phase 7: Build & Release Pipeline
- Updated GitHub Actions workflows for LLMX binary names
- Fixed rust-release.yml to reference llmx-rs/ instead of codex-rs/
- Updated CI/CD pipelines for new package names
- Made Apple code signing optional in release workflow
- Enhanced npm packaging resilience for partial platform builds
- Added Windows sandbox support to workspace
- Updated dotslash configuration for new binary names

### Phase 8: Final Polish
- Renamed all assets (.github images, labels, templates)
- Updated VSCode and DevContainer configurations
- Fixed all clippy warnings and formatting issues
- Applied cargo fmt and prettier formatting across codebase
- Updated issue templates and pull request templates
- Fixed all remaining UI text references

## Technical Details

**Breaking Changes:**
- Binary name changed from `codex` to `llmx`
- Config directory changed from `~/.codex/` to `~/.llmx/`
- Environment variables renamed (CODEX_* → LLMX_*)
- npm package renamed to `@valknar/llmx`

**New Features:**
- Support for 100+ LLM providers via LiteLLM
- Unified authentication with LLMX_API_KEY
- Enhanced model provider detection and handling
- Improved error handling and fallback mechanisms

**Files Changed:**
- 578 files modified across Rust, TypeScript, and documentation
- 30+ Rust crates renamed and updated
- Complete rebrand of UI, CLI, and documentation
- All tests updated and passing

**Dependencies:**
- Updated Cargo.lock with new package names
- Updated npm dependencies in llmx-cli
- Enhanced OpenAPI models for LLMX backend

This release establishes LLMX as a standalone project with comprehensive LiteLLM
integration, maintaining full backward compatibility with existing functionality
while opening support for a wide ecosystem of LLM providers.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Sebastian Krüger <support@pivoine.art>

docs/release_management.md

@@ -1,30 +1,30 @@
 # Release Management
 
-Currently, we made Codex binaries available in three places:
+Currently, we made LLMX binaries available in three places:
 
-- GitHub Releases https://github.com/openai/codex/releases/
-- `@openai/codex` on npm: https://www.npmjs.com/package/@openai/codex
-- `codex` on Homebrew: https://formulae.brew.sh/cask/codex
+- GitHub Releases https://github.com/valknar/llmx/releases/
+- `@llmx/llmx` on npm: https://www.npmjs.com/package/@llmx/llmx
+- `llmx` on Homebrew: https://formulae.brew.sh/cask/llmx
 
 # Cutting a Release
 
-Run the `codex-rs/scripts/create_github_release` script in the repository to publish a new release. The script will choose the appropriate version number depending on the type of release you are creating.
+Run the `llmx-rs/scripts/create_github_release` script in the repository to publish a new release. The script will choose the appropriate version number depending on the type of release you are creating.
 
 To cut a new alpha release from `main` (feel free to cut alphas liberally):
 
 ```
-./codex-rs/scripts/create_github_release --publish-alpha
+./llmx-rs/scripts/create_github_release --publish-alpha
 ```
 
 To cut a new _public_ release from `main` (which requires more caution), run:
 
 ```
-./codex-rs/scripts/create_github_release --publish-release
+./llmx-rs/scripts/create_github_release --publish-release
 ```
 
 TIP: Add the `--dry-run` flag to report the next version number for the respective release and exit.
 
-Running the publishing script will kick off a GitHub Action to build the release, so go to https://github.com/openai/codex/actions/workflows/rust-release.yml to find the corresponding workflow. (Note: we should automate finding the workflow URL with `gh`.)
+Running the publishing script will kick off a GitHub Action to build the release, so go to https://github.com/valknar/llmx/actions/workflows/rust-release.yml to find the corresponding workflow. (Note: we should automate finding the workflow URL with `gh`.)
 
 When the workflow finishes, the GitHub Release is "done," but you still have to consider npm and Homebrew.
 
@@ -34,12 +34,12 @@ The GitHub Action is responsible for publishing to npm.
 
 ## Publishing to Homebrew
 
-For Homebrew, we ship Codex as a cask. Homebrew's automation system checks our GitHub repo every few hours for a new release and will open a PR to update the cask with the latest binary.
+For Homebrew, we ship LLMX as a cask. Homebrew's automation system checks our GitHub repo every few hours for a new release and will open a PR to update the cask with the latest binary.
 
 Inevitably, you just have to refresh this page periodically to see if the release has been picked up by their automation system:
 
-https://github.com/Homebrew/homebrew-cask/pulls?q=%3Apr+codex
+https://github.com/Homebrew/homebrew-cask/pulls?q=%3Apr+llmx
 
 For reference, our Homebrew cask lives at:
 
-https://github.com/Homebrew/homebrew-cask/blob/main/Casks/c/codex.rb
+https://github.com/Homebrew/homebrew-cask/blob/main/Casks/c/llmx.rb