Phase 2: Rust Workspace Transformation (Part 1)

- Renamed directory: codex-backend-openapi-models -> llmx-backend-openapi-models
- Updated all Cargo.toml files:
  - Package names: codex-* -> llmx-*
  - Library names: codex_* -> llmx_*
  - Workspace dependencies updated
- Renamed Rust source files:
  - codex*.rs -> llmx*.rs (all modules)
  - codex_conversation -> llmx_conversation
  - codex_delegate -> llmx_delegate
  - codex_message_processor -> llmx_message_processor
  - codex_tool_* -> llmx_tool_*
- Updated all Rust imports:
  - use codex_* -> use llmx_*
  - mod codex* -> mod llmx*
- Updated environment variables in code:
  - CODEX_HOME -> LLMX_HOME
  - .codex -> .llmx paths
- Updated protocol crate lib name for proper linking

Note: Some compilation errors remain (type inference issues) but all
renaming is complete. Will fix compilation in next phase.

🤖 Generated with Claude Code

llmx-rs/mcp-server/tests/common/mcp_process.rs

@@ -11,7 +11,7 @@ use tokio::process::ChildStdout;
 
 use anyhow::Context;
 use assert_cmd::prelude::*;
-use codex_mcp_server::CodexToolCallParam;
+use llmx_mcp_server::CodexToolCallParam;
 
 use mcp_types::CallToolRequestParams;
 use mcp_types::ClientCapabilities;
@@ -148,7 +148,7 @@ impl McpProcess {
             os_info.os_type(),
             os_info.version(),
             os_info.architecture().unwrap_or("unknown"),
-            codex_core::terminal::user_agent()
+            llmx_core::terminal::user_agent()
         );
         assert_eq!(
             JSONRPCMessage::Response(JSONRPCResponse {