fix: prioritize explicit shell paths over PATH in detection and resolution

The shell detection and resolution were checking PATH entries before
explicit paths, causing the wrong PowerShell version to be found.

Changes:
- lib.rs: Check PowerShell 7 explicit paths BEFORE PATH entries in
  get_available_shells()
- manager.rs: Check explicit paths BEFORE PATH entries in
  resolve_shell_path()

This ensures PowerShell 7 (C:\Program Files\PowerShell\7\pwsh.exe) is
found and used when installed, rather than falling back to Windows
PowerShell 5 (powershell.exe) from PATH.

Fixes #59

Co-Authored-By: Claude <noreply@anthropic.com>

Author: gnoviawan

src-tauri/src/lib.rs

@@ -204,10 +204,17 @@ fn get_available_shells() -> Vec<ShellInfo> {
 
     #[cfg(target_os = "windows")]
     {
+        // CRITICAL: Check explicit paths FIRST, then PATH entries
+        // This ensures the correct shell is found when multiple versions exist
         let mut candidates = vec![
+            // PowerShell 7 explicit paths (checked first)
+            ("pwsh", r"C:\Program Files\PowerShell\7\pwsh.exe", None),
+            ("pwsh", r"C:\Program Files\PowerShell\6\pwsh.exe", None),
+            // Windows PowerShell 5 (explicit path)
+            ("powershell", r"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe", None),
+            // PATH-based fallbacks (checked last)
+            ("pwsh", "pwsh.exe", None),
             ("powershell", "powershell.exe", None),
-            ("pwsh", "pwsh.exe", None), // PowerShell 7 via PATH
-            ("pwsh", "C:\\Program Files\\PowerShell\\7\\pwsh.exe", None), // PowerShell 7 explicit path
             ("cmd", "cmd.exe", None),
             ("wsl", "wsl.exe", None),
         ];

src-tauri/src/pty/manager.rs

@@ -994,12 +994,17 @@ impl PtyManager {
             }
 
             // Try PowerShell variants
+            // CRITICAL: Check explicit paths FIRST, then PATH
             if shell == "powershell" || shell == "pwsh" {
                 let paths = vec![
-                    "pwsh.exe",
-                    "powershell.exe",
+                    // PowerShell 7 explicit paths (checked first)
                     r"C:\Program Files\PowerShell\7\pwsh.exe",
                     r"C:\Program Files\PowerShell\6\pwsh.exe",
+                    // Windows PowerShell 5 explicit path
+                    r"C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe",
+                    // PATH-based fallbacks (checked last)
+                    "pwsh.exe",
+                    "powershell.exe",
                 ];
                 for path in paths {
                     if let Some(abs_path) = self.get_absolute_shell_path(path) {