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/app-server/tests/common/auth_fixtures.rs

@@ -6,11 +6,11 @@ use base64::Engine;
 use base64::engine::general_purpose::URL_SAFE_NO_PAD;
 use chrono::DateTime;
 use chrono::Utc;
-use codex_core::auth::AuthCredentialsStoreMode;
-use codex_core::auth::AuthDotJson;
-use codex_core::auth::save_auth;
-use codex_core::token_data::TokenData;
-use codex_core::token_data::parse_id_token;
+use llmx_core::auth::AuthCredentialsStoreMode;
+use llmx_core::auth::AuthDotJson;
+use llmx_core::auth::save_auth;
+use llmx_core::token_data::TokenData;
+use llmx_core::token_data::parse_id_token;
 use serde_json::json;
 
 /// Builder for writing a fake ChatGPT auth.json in tests.