Prevent Lua injection in Neovim error notifications

[phillco]

Motivation

• Prevent execution of attacker-controlled Lua by removing string interpolation of error messages into generated Lua code for Neovim notifications.

Description

• Replace unsafe interpolation in showErrorMessage with an argument-bound call by using vim.notify(...) as the Lua snippet and passing the message via executeLua arguments so user text is treated as data.

Testing

• Ran the repository lint suite with pnpm run lint, which completed successfully.

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Codex Task