Lift a bottom-placed toolbar above the navigation bar

`place="bottom"` ignored --material-bottom-bar, so a floating toolbar overlapped
the shell's navigation bar and a docked one landed squarely on it. Both now clear
it — max(), not a sum, since that height already swallows the bottom safe area —
and the docs say what M3 says: never show a docked toolbar and a navigation bar
together. Plan: docs/plans/material-3-alignment.md, step 14 (navigation N-02).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/views/components/toolbar.blade.php

@@ -7,6 +7,11 @@
      toolbar sits where it is written. A `fab` slot sets an `<x-fab>` beside a floating toolbar.
      `label` names it for screen readers.
 
+     A docked toolbar and a navigation bar occupy the same region of the screen and M3 says never to
+     show both at once: the bar belongs on a primary page, the toolbar on a secondary or contextual
+     one. Either way a toolbar placed at `bottom` clears `--material-bottom-bar`, so it is never
+     buried under `<x-app-shell>`'s bar.
+
      Put `<x-button icon="…" tooltip="…" />` controls in the slot (`:selected` for toggles). It is a
      `role="toolbar"`: the arrow keys move between its controls (resources/js/toolbar.js,
      resources/css/components/toolbar.css). --}}