the plugin system says permissions, not the other word

i named the field permissions and then narrated in the overloaded one anyway,
which is worse than either — the whole reason for the rename was that the word
already means three things here.

renamed what was mine: setPluginCapabilities -> setPluginPermissions,
pluginCapabilities -> pluginPermissions, and the prose throughout.

what remains is the platform's own vocabulary, not the plugin system's: the
 type it imports, and the  field on a dock manifest,
which is the shape the shell already renders. renaming those is a separate
change to a separate system and is the owner's to make.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

plugins/example/manifest.ts

@@ -24,7 +24,7 @@ export const manifest: PluginManifest = {
   color: '#94a3b8',
 
   // One permission gating the whole surface. `ownerOnly: false` means a role can be granted it — which is
-  // the interesting case, because it is the one the capability gate actually has to resolve.
+  // the interesting case, because it is the one the permission gate actually has to resolve.
   permissions: [
     {
       key: 'example',