fix: use shell.path instead of shell.name when spawning terminal

When users select "PowerShell 7" from the shell dropdown, the terminal
was spawning with Windows PowerShell 5 instead. This happened because
the frontend passed shell.name ("pwsh") to the spawn function, but the
backend's resolve_shell_path() couldn't find pwsh.exe in PATH and fell
back to powershell.exe.

By passing shell.path (the already-detected absolute path), we bypass
PATH resolution entirely and use the correct shell executable.

Fixes #59

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

Author: gnoviawan

src/renderer/layouts/WorkspaceLayout.tsx

@@ -761,7 +761,7 @@ export default function WorkspaceLayout(): React.JSX.Element {
                             handleCreateTerminalInPane(paneId)
                           }}
                           onNewTerminalWithShell={(paneId, shell) => {
-                            handleCreateTerminalInPane(paneId, shell.name)
+                            handleCreateTerminalInPane(paneId, shell.path)
                           }}
                           onCloseTerminal={handleCloseTerminal}
                           onRenameTerminal={renameTerminal}