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>

llmx-rs/async-utils/src/lib.rs

@@ -0,0 +1,86 @@
+use async_trait::async_trait;
+use std::future::Future;
+use tokio_util::sync::CancellationToken;
+
+#[derive(Debug, PartialEq, Eq)]
+pub enum CancelErr {
+    Cancelled,
+}
+
+#[async_trait]
+pub trait OrCancelExt: Sized {
+    type Output;
+
+    async fn or_cancel(self, token: &CancellationToken) -> Result<Self::Output, CancelErr>;
+}
+
+#[async_trait]
+impl<F> OrCancelExt for F
+where
+    F: Future + Send,
+    F::Output: Send,
+{
+    type Output = F::Output;
+
+    async fn or_cancel(self, token: &CancellationToken) -> Result<Self::Output, CancelErr> {
+        tokio::select! {
+            _ = token.cancelled() => Err(CancelErr::Cancelled),
+            res = self => Ok(res),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use pretty_assertions::assert_eq;
+    use std::time::Duration;
+    use tokio::task;
+    use tokio::time::sleep;
+
+    #[tokio::test]
+    async fn returns_ok_when_future_completes_first() {
+        let token = CancellationToken::new();
+        let value = async { 42 };
+
+        let result = value.or_cancel(&token).await;
+
+        assert_eq!(Ok(42), result);
+    }
+
+    #[tokio::test]
+    async fn returns_err_when_token_cancelled_first() {
+        let token = CancellationToken::new();
+        let token_clone = token.clone();
+
+        let cancel_handle = task::spawn(async move {
+            sleep(Duration::from_millis(10)).await;
+            token_clone.cancel();
+        });
+
+        let result = async {
+            sleep(Duration::from_millis(100)).await;
+            7
+        }
+        .or_cancel(&token)
+        .await;
+
+        cancel_handle.await.expect("cancel task panicked");
+        assert_eq!(Err(CancelErr::Cancelled), result);
+    }
+
+    #[tokio::test]
+    async fn returns_err_when_token_already_cancelled() {
+        let token = CancellationToken::new();
+        token.cancel();
+
+        let result = async {
+            sleep(Duration::from_millis(50)).await;
+            5
+        }
+        .or_cancel(&token)
+        .await;
+
+        assert_eq!(Err(CancelErr::Cancelled), result);
+    }
+}