Merge pull request #33193 from backstage/rugvip/nfs-icon-sizing

frontend-app-api: align icon sizing in nfs

.changeset/nfs-icon-alpha-plugins.md

@@ -0,0 +1,12 @@
+---
+'@backstage/plugin-api-docs': patch
+'@backstage/plugin-catalog': patch
+'@backstage/plugin-catalog-unprocessed-entities': patch
+'@backstage/plugin-devtools': patch
+'@backstage/plugin-scaffolder': patch
+'@backstage/plugin-search': patch
+'@backstage/plugin-techdocs': patch
+'@backstage/plugin-user-settings': patch
+---
+
+Updated alpha plugin icons to follow the new frontend icon sizing rules when rendered in plugin and navigation surfaces.

.changeset/nfs-icon-foundations.md

@@ -0,0 +1,7 @@
+---
+'@backstage/core-components': patch
+'@backstage/frontend-app-api': patch
+'@backstage/frontend-plugin-api': patch
+---
+
+Clarified the `IconElement` sizing contract for the new frontend system and aligned legacy system icon rendering with the new icon API.

.changeset/nfs-icon-plugin-app.md

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+---
+'@backstage/plugin-app': patch
+---
+
+The app nav now falls back to `plugin.icon` for navigation items that don't have an explicit icon set.