Say how the rail's FAB overrides win, and that rail-collapsed: is gone

Plan step 36, navigation review. navigation-rail.css claimed each FAB
override beats fab.css by specificity alone; the collapsed FAB's gap
and minimum width tie with fab.css's extended-size rules and win by
order, which the file's own import of fab.css guarantees. The rail
view pointed at one file for the collapsed conditions that four files
write out. UPGRADE.md now says applications lose the `rail-collapsed:`
variant the development skill used to teach.

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

resources/views/components/navigation-rail.blade.php

@@ -48,8 +48,9 @@
      Anything else inside can take both shapes by matching the rail's own state directly, the same
      selectors resources/css/components/navigation-rail.css uses for every branch of "collapsed" —
      `data-md-navigation-rail`'s value, `:not([data-md-open])`, and the window band each mode
-     collapses in; that file is the one place the numbers need to stay right, rather than a
-     Tailwind variant repeating them. Nothing that shows while collapsed may be wider than 96px.
+     collapses in (its header lists them). Every rule in the package that draws a collapsed shape
+     writes them out, and tests/Feature/Components/NavigationRailTest.php keeps each copy to the same
+     conditions. Nothing that shows while collapsed may be wider than 96px.
 
      Props: `label` names the landmark ("Main"); `width` is the expanded width (`256px`, held
      between M3's 220 and 360dp) — or the word `narrow`, M3's other *collapsed* width