Add CLAUDE.md with development guidance (#661)

* Add CLAUDE.md with development guidance

Provides essential commands and architecture overview for Claude Code to work effectively in this repository.

* Fix clippy warnings

Apply automatic fixes from cargo lint-fix.

* Update CLAUDE.md and apply code formatting

Add guidance to run cargo fmt after making changes and apply formatting.

CLAUDE.md

@@ -0,0 +1,27 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Development Commands
+
+- `cargo run -- <args>` - Run CLI during development
+- `cargo test` - Run tests
+- `cargo lint-fix` - Fix linting issues automatically (run after making changes)
+- `cargo fmt` - Format code (run after making changes)
+- `cargo clippy` - Check for linting issues
+- `nix-shell` - Enter dev environment with dependencies
+
+## Architecture
+
+- **Commands**: `src/commands/` - CLI commands using clap derives, each with `exec()` function
+- **Controllers**: `src/controllers/` - Business logic for Railway entities (project, service, deployment)  
+- **GraphQL**: `src/gql/` - Generated type-safe queries/mutations for Railway API
+- **Config**: `src/config.rs` - Authentication and project settings
+- **Workspace**: `src/workspace.rs` - Multi-project context handling
+
+### Command System
+Commands use a macro system in `main.rs`. The `commands!` macro generates routing for modules in `src/commands/`.
+
+### Authentication
+- Project tokens via `RAILWAY_TOKEN` environment variable
+- User tokens via OAuth flow stored in config directory

src/commands/add.rs

@@ -204,12 +204,12 @@ fn prompt_name(service: Option<Option<String>>) -> Result<Option<String>> {
             Ok(None)
         }
     } else if std::io::stdout().is_terminal() {
-        return Ok(Some(prompt_text_with_placeholder_if_blank(
+        Ok(Some(prompt_text_with_placeholder_if_blank(
             "Enter a service name",
             "<leave blank for randomly generated>",
             "<randomly generated>",
         )?)
-        .filter(|s| !s.trim().is_empty()));
+        .filter(|s| !s.trim().is_empty()))
     } else {
         fake_select("Enter a service name", "<randomly generated>");
         Ok(None)

src/util/check_update.rs

@@ -5,19 +5,11 @@ use dirs::home_dir;
 
 use super::compare_semver::compare_semver;
 
-#[derive(serde::Serialize, serde::Deserialize)]
+#[derive(serde::Serialize, serde::Deserialize, Default)]
 pub struct UpdateCheck {
     pub last_update_check: Option<chrono::DateTime<chrono::Utc>>,
     pub latest_version: Option<String>,
 }
-impl Default for UpdateCheck {
-    fn default() -> Self {
-        Self {
-            last_update_check: None,
-            latest_version: None,
-        }
-    }
-}
 impl UpdateCheck {
     pub fn write(&self) -> anyhow::Result<()> {
         let home = home_dir().context("Failed to get home directory")?;
@@ -64,7 +56,7 @@ pub async fn check_update(force: bool) -> anyhow::Result<Option<String>> {
     let response = response.json::<GithubApiRelease>().await?;
     let latest_version = response.tag_name.trim_start_matches('v');
 
-    match compare_semver(env!("CARGO_PKG_VERSION"), &latest_version) {
+    match compare_semver(env!("CARGO_PKG_VERSION"), latest_version) {
         Ordering::Less => {
             let update = UpdateCheck {
                 last_update_check: Some(chrono::Utc::now()),