Move pickServer() into the try-catch in runLsp() so UnsupportedExtensionError
is caught directly. Add message-based fallback in both runLsp() and
runDiagnostics() to handle daemon-wrapped errors that come through as plain
Error instances rather than the original typed exception.
This eliminates spurious 'No LSP server registered' warnings during auto-check
after edit/write on files without LSP support (e.g. .md, .txt, .sh).
Add /lsp-servers, /lsp-disable, /lsp-enable, and /lsp-destroy TUI commands.
Disabled servers are tracked in-memory per-extension-instance; the shared
daemon is never mutated by disable/enable. When all servers are disabled,
LSP tools are removed from the active tool set so the LLM won't attempt them.
Also adds a destroy_server daemon operation that kills running LspClient
entries by server ID or all entries.
