feat: add shared claude binary detection module

Introduces a dedicated module for detecting Claude Code binary installations
with support for multiple sources including NVM, aliased paths, and
version-based selection. This shared module improves the reliability of
finding Claude installations across different environments.

Key features:
- Supports multiple installation sources (NVM, system, homebrew, npm, yarn, bun)
- Handles aliased paths from 'which' command
- Version-aware selection to prefer latest installations
- Database caching of discovered binary paths
- Comprehensive logging for debugging
- Environment variable preservation for NVM compatibility

The implementation is inspired by:
- https://github.com/getAsterisk/claudia/pull/3
- https://github.com/getAsterisk/claudia/pull/4

src-tauri/src/claude_binary.rs

@@ -0,0 +1,360 @@
+/// Shared module for detecting Claude Code binary installations
+/// Supports NVM installations, aliased paths, and version-based selection
+use std::path::PathBuf;
+use std::process::Command;
+use log::{info, warn, debug, error};
+use anyhow::Result;
+use std::cmp::Ordering;
+use tauri::Manager;
+
+/// Represents a Claude installation with metadata
+#[derive(Debug, Clone)]
+pub struct ClaudeInstallation {
+    /// Full path to the Claude binary
+    pub path: String,
+    /// Version string if available
+    pub version: Option<String>,
+    /// Source of discovery (e.g., "nvm", "system", "homebrew", "which")
+    pub source: String,
+}
+
+/// Main function to find the Claude binary
+/// Checks database first, then discovers all installations and selects the best one
+pub fn find_claude_binary(app_handle: &tauri::AppHandle) -> Result<String, String> {
+    info!("Searching for claude binary...");
+    
+    // First check if we have a stored path in the database
+    if let Ok(app_data_dir) = app_handle.path().app_data_dir() {
+        let db_path = app_data_dir.join("agents.db");
+        if db_path.exists() {
+            if let Ok(conn) = rusqlite::Connection::open(&db_path) {
+                if let Ok(stored_path) = conn.query_row(
+                    "SELECT value FROM app_settings WHERE key = 'claude_binary_path'",
+                    [],
+                    |row| row.get::<_, String>(0),
+                ) {
+                    info!("Found stored claude path in database: {}", stored_path);
+                    let path_buf = PathBuf::from(&stored_path);
+                    if path_buf.exists() && path_buf.is_file() {
+                        return Ok(stored_path);
+                    } else {
+                        warn!("Stored claude path no longer exists: {}", stored_path);
+                    }
+                }
+            }
+        }
+    }
+    
+    // Discover all available installations
+    let installations = discover_all_installations();
+    
+    if installations.is_empty() {
+        error!("Could not find claude binary in any location");
+        return Err("Claude Code not found. Please ensure it's installed in one of these locations: PATH, /usr/local/bin, /opt/homebrew/bin, ~/.nvm/versions/node/*/bin, ~/.claude/local, ~/.local/bin".to_string());
+    }
+    
+    // Log all found installations
+    for installation in &installations {
+        info!("Found Claude installation: {:?}", installation);
+    }
+    
+    // Select the best installation (highest version)
+    if let Some(best) = select_best_installation(installations) {
+        info!("Selected Claude installation: path={}, version={:?}, source={}", 
+              best.path, best.version, best.source);
+        Ok(best.path)
+    } else {
+        Err("No valid Claude installation found".to_string())
+    }
+}
+
+/// Discovers all Claude installations on the system
+fn discover_all_installations() -> Vec<ClaudeInstallation> {
+    let mut installations = Vec::new();
+    
+    // 1. Try 'which' command first (now works in production)
+    if let Some(installation) = try_which_command() {
+        installations.push(installation);
+    }
+    
+    // 2. Check NVM paths
+    installations.extend(find_nvm_installations());
+    
+    // 3. Check standard paths
+    installations.extend(find_standard_installations());
+    
+    // Remove duplicates by path
+    let mut unique_paths = std::collections::HashSet::new();
+    installations.retain(|install| unique_paths.insert(install.path.clone()));
+    
+    installations
+}
+
+/// Try using the 'which' command to find Claude
+fn try_which_command() -> Option<ClaudeInstallation> {
+    debug!("Trying 'which claude' to find binary...");
+    
+    match Command::new("which").arg("claude").output() {
+        Ok(output) if output.status.success() => {
+            let output_str = String::from_utf8_lossy(&output.stdout).trim().to_string();
+            
+            if output_str.is_empty() {
+                return None;
+            }
+            
+            // Parse aliased output: "claude: aliased to /path/to/claude"
+            let path = if output_str.starts_with("claude:") && output_str.contains("aliased to") {
+                output_str.split("aliased to")
+                    .nth(1)
+                    .map(|s| s.trim().to_string())
+            } else {
+                Some(output_str)
+            }?;
+            
+            debug!("'which' found claude at: {}", path);
+            
+            // Verify the path exists
+            if !PathBuf::from(&path).exists() {
+                warn!("Path from 'which' does not exist: {}", path);
+                return None;
+            }
+            
+            // Get version
+            let version = get_claude_version(&path).ok().flatten();
+            
+            Some(ClaudeInstallation {
+                path,
+                version,
+                source: "which".to_string(),
+            })
+        }
+        _ => None,
+    }
+}
+
+/// Find Claude installations in NVM directories
+fn find_nvm_installations() -> Vec<ClaudeInstallation> {
+    let mut installations = Vec::new();
+    
+    if let Ok(home) = std::env::var("HOME") {
+        let nvm_dir = PathBuf::from(&home).join(".nvm").join("versions").join("node");
+        
+        debug!("Checking NVM directory: {:?}", nvm_dir);
+        
+        if let Ok(entries) = std::fs::read_dir(&nvm_dir) {
+            for entry in entries.flatten() {
+                if entry.file_type().map(|t| t.is_dir()).unwrap_or(false) {
+                    let claude_path = entry.path().join("bin").join("claude");
+                    
+                    if claude_path.exists() && claude_path.is_file() {
+                        let path_str = claude_path.to_string_lossy().to_string();
+                        let node_version = entry.file_name().to_string_lossy().to_string();
+                        
+                        debug!("Found Claude in NVM node {}: {}", node_version, path_str);
+                        
+                        // Get Claude version
+                        let version = get_claude_version(&path_str).ok().flatten();
+                        
+                        installations.push(ClaudeInstallation {
+                            path: path_str,
+                            version,
+                            source: format!("nvm ({})", node_version),
+                        });
+                    }
+                }
+            }
+        }
+    }
+    
+    installations
+}
+
+/// Check standard installation paths
+fn find_standard_installations() -> Vec<ClaudeInstallation> {
+    let mut installations = Vec::new();
+    
+    // Common installation paths for claude
+    let mut paths_to_check: Vec<(String, String)> = vec![
+        ("/usr/local/bin/claude".to_string(), "system".to_string()),
+        ("/opt/homebrew/bin/claude".to_string(), "homebrew".to_string()),
+        ("/usr/bin/claude".to_string(), "system".to_string()),
+        ("/bin/claude".to_string(), "system".to_string()),
+    ];
+    
+    // Also check user-specific paths
+    if let Ok(home) = std::env::var("HOME") {
+        paths_to_check.extend(vec![
+            (format!("{}/.claude/local/claude", home), "claude-local".to_string()),
+            (format!("{}/.local/bin/claude", home), "local-bin".to_string()),
+            (format!("{}/.npm-global/bin/claude", home), "npm-global".to_string()),
+            (format!("{}/.yarn/bin/claude", home), "yarn".to_string()),
+            (format!("{}/.bun/bin/claude", home), "bun".to_string()),
+            (format!("{}/bin/claude", home), "home-bin".to_string()),
+            // Check common node_modules locations
+            (format!("{}/node_modules/.bin/claude", home), "node-modules".to_string()),
+            (format!("{}/.config/yarn/global/node_modules/.bin/claude", home), "yarn-global".to_string()),
+        ]);
+    }
+    
+    // Check each path
+    for (path, source) in paths_to_check {
+        let path_buf = PathBuf::from(&path);
+        if path_buf.exists() && path_buf.is_file() {
+            debug!("Found claude at standard path: {} ({})", path, source);
+            
+            // Get version
+            let version = get_claude_version(&path).ok().flatten();
+            
+            installations.push(ClaudeInstallation {
+                path,
+                version,
+                source,
+            });
+        }
+    }
+    
+    // Also check if claude is available in PATH (without full path)
+    if let Ok(output) = Command::new("claude").arg("--version").output() {
+        if output.status.success() {
+            debug!("claude is available in PATH");
+            let version = extract_version_from_output(&output.stdout);
+            
+            installations.push(ClaudeInstallation {
+                path: "claude".to_string(),
+                version,
+                source: "PATH".to_string(),
+            });
+        }
+    }
+    
+    installations
+}
+
+/// Get Claude version by running --version command
+fn get_claude_version(path: &str) -> Result<Option<String>, String> {
+    match Command::new(path).arg("--version").output() {
+        Ok(output) => {
+            if output.status.success() {
+                Ok(extract_version_from_output(&output.stdout))
+            } else {
+                Ok(None)
+            }
+        }
+        Err(e) => {
+            warn!("Failed to get version for {}: {}", path, e);
+            Ok(None)
+        }
+    }
+}
+
+/// Extract version string from command output
+fn extract_version_from_output(stdout: &[u8]) -> Option<String> {
+    let output_str = String::from_utf8_lossy(stdout);
+    
+    // Extract version: first token before whitespace that looks like a version
+    output_str.split_whitespace()
+        .find(|token| {
+            // Version usually contains dots and numbers
+            token.chars().any(|c| c == '.') && 
+            token.chars().any(|c| c.is_numeric())
+        })
+        .map(|s| s.to_string())
+}
+
+/// Select the best installation based on version
+fn select_best_installation(installations: Vec<ClaudeInstallation>) -> Option<ClaudeInstallation> {
+    installations.into_iter()
+        .filter(|i| {
+            // Prefer installations with known versions
+            i.version.is_some() || i.path == "claude"
+        })
+        .max_by(|a, b| {
+            // First compare by version presence
+            match (&a.version, &b.version) {
+                (Some(v1), Some(v2)) => compare_versions(v1, v2),
+                (Some(_), None) => Ordering::Greater,
+                (None, Some(_)) => Ordering::Less,
+                (None, None) => {
+                    // Both have no version, prefer non-PATH entries
+                    if a.path == "claude" && b.path != "claude" {
+                        Ordering::Less
+                    } else if a.path != "claude" && b.path == "claude" {
+                        Ordering::Greater
+                    } else {
+                        Ordering::Equal
+                    }
+                }
+            }
+        })
+}
+
+/// Compare two version strings
+fn compare_versions(a: &str, b: &str) -> Ordering {
+    // Simple semantic version comparison
+    let a_parts: Vec<u32> = a.split('.')
+        .filter_map(|s| {
+            // Handle versions like "1.0.17-beta" by taking only numeric part
+            s.chars()
+                .take_while(|c| c.is_numeric())
+                .collect::<String>()
+                .parse()
+                .ok()
+        })
+        .collect();
+    
+    let b_parts: Vec<u32> = b.split('.')
+        .filter_map(|s| {
+            s.chars()
+                .take_while(|c| c.is_numeric())
+                .collect::<String>()
+                .parse()
+                .ok()
+        })
+        .collect();
+    
+    // Compare each part
+    for i in 0..std::cmp::max(a_parts.len(), b_parts.len()) {
+        let a_val = a_parts.get(i).unwrap_or(&0);
+        let b_val = b_parts.get(i).unwrap_or(&0);
+        match a_val.cmp(b_val) {
+            Ordering::Equal => continue,
+            other => return other,
+        }
+    }
+    
+    Ordering::Equal
+}
+
+/// Helper function to create a Command with proper environment variables
+/// This ensures commands like Claude can find Node.js and other dependencies
+pub fn create_command_with_env(program: &str) -> Command {
+    let mut cmd = Command::new(program);
+    
+    // Inherit essential environment variables from parent process
+    for (key, value) in std::env::vars() {
+        // Pass through PATH and other essential environment variables
+        if key == "PATH" || key == "HOME" || key == "USER" 
+            || key == "SHELL" || key == "LANG" || key == "LC_ALL" || key.starts_with("LC_")
+            || key == "NODE_PATH" || key == "NVM_DIR" || key == "NVM_BIN" 
+            || key == "HOMEBREW_PREFIX" || key == "HOMEBREW_CELLAR" {
+            debug!("Inheriting env var: {}={}", key, value);
+            cmd.env(&key, &value);
+        }
+    }
+    
+    // Add NVM support if the program is in an NVM directory
+    if program.contains("/.nvm/versions/node/") {
+        if let Some(node_bin_dir) = std::path::Path::new(program).parent() {
+            // Ensure the Node.js bin directory is in PATH
+            let current_path = std::env::var("PATH").unwrap_or_default();
+            let node_bin_str = node_bin_dir.to_string_lossy();
+            if !current_path.contains(&node_bin_str.as_ref()) {
+                let new_path = format!("{}:{}", node_bin_str, current_path);
+                debug!("Adding NVM bin directory to PATH: {}", node_bin_str);
+                cmd.env("PATH", new_path);
+            }
+        }
+    }
+    
+    cmd
+} 

src-tauri/src/lib.rs

@@ -5,6 +5,7 @@ pub mod commands;
 pub mod sandbox;
 pub mod checkpoint;
 pub mod process;
+pub mod claude_binary;
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {

src-tauri/src/main.rs

@@ -5,6 +5,7 @@ mod commands;
 mod sandbox;
 mod checkpoint;
 mod process;
+mod claude_binary;
 
 use tauri::Manager;
 use commands::claude::{