### Fixed

- `BufWritePre` formatters (e.g. conform.nvim format-on-save) now run on
  autosave. The trigger autocmd now uses `nested = true`, so the `:write`
  invoked from inside the `InsertLeave` / `TextChanged` / `FocusLost`
  handler fires nested autocmds (see `:help autocmd-nested`).

### Changed

- Skip saves for unmodified, unnamed, or special (`buftype`) buffers instead
  of always attempting a write.
- Drop `:wall` — autosave only writes the buffer the event fired on.
- Use `silent` (not `silent!`) so write errors surface instead of being
  swallowed.