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/core/templates/compact/prompt.md

@@ -0,0 +1,9 @@
+You are performing a CONTEXT CHECKPOINT COMPACTION. Create a handoff summary for another LLM that will resume the task.
+
+Include:
+- Current progress and key decisions made
+- Important context, constraints, or user preferences
+- What remains to be done (clear next steps)
+- Any critical data, examples, or references needed to continue
+
+Be concise, structured, and focused on helping the next LLM seamlessly continue the work.

llmx-rs/core/templates/review/exit_interrupted.xml

@@ -0,0 +1,8 @@
+<user_action>
+  <context>User initiated a review task, but was interrupted. If user asks about this, tell them to re-initiate a review with `/review` and wait for it to complete.</context>
+  <action>review</action>
+  <results>
+  None.
+  </results>
+</user_action>
+

llmx-rs/core/templates/review/exit_success.xml

@@ -0,0 +1,8 @@
+<user_action>
+  <context>User initiated a review task. Here's the full review output from reviewer model. User may select one or more comments to resolve.</context>
+  <action>review</action>
+  <results>
+  {results}
+  </results>
+  </user_action>
+

llmx-rs/core/templates/review/history_message_completed.md

@@ -0,0 +1,8 @@
+<user_action>
+  <context>User initiated a review task. Here's the full review output from reviewer model. User may select one or more comments to resolve.</context>
+  <action>review</action>
+  <results>
+  {findings}
+  </results>
+</user_action>
+

llmx-rs/core/templates/review/history_message_interrupted.md

@@ -0,0 +1,8 @@
+<user_action>
+  <context>User initiated a review task, but was interrupted. If user asks about this, tell them to re-initiate a review with `/review` and wait for it to complete.</context>
+  <action>review</action>
+  <results>
+  None.
+  </results>
+</user_action>
+

llmx-rs/core/templates/sandboxing/assessment_prompt.md

@@ -0,0 +1,24 @@
+You are a security analyst evaluating shell commands that were blocked by a sandbox. Given the provided metadata, summarize the command's likely intent and assess the risk to help the user decide whether to approve command execution. Return strictly valid JSON with the keys:
+- description (concise summary of command intent and potential effects, no more than one sentence, use present tense)
+- risk_level ("low", "medium", or "high")
+Risk level examples:
+- low: read-only inspections, listing files, printing configuration, fetching artifacts from trusted sources
+- medium: modifying project files, installing dependencies
+- high: deleting or overwriting data, exfiltrating secrets, escalating privileges, or disabling security controls
+If information is insufficient, choose the most cautious risk level supported by the evidence.
+Respond with JSON only, without markdown code fences or extra commentary.
+
+---
+
+Command metadata:
+Platform: {{ platform }}
+Sandbox policy: {{ sandbox_policy }}
+{% if let Some(roots) = filesystem_roots %}
+Filesystem roots: {{ roots }}
+{% endif %}
+Working directory: {{ working_directory }}
+Command argv: {{ command_argv }}
+Command (joined): {{ command_joined }}
+{% if let Some(message) = sandbox_failure_message %}
+Sandbox failure message: {{ message }}
+{% endif %}