Add Emby and Seerr widgets

Emby mirrors the Jellyfin widget (library blocks + now playing).
Seerr shows pending/approved/completed request counts - currently
403ing on request/count since the configured API key looks like a
per-user key rather than the admin key from Settings > General.
Keys documented in .env.example.

services.yaml

@@ -447,6 +447,12 @@
         icon: emby.svg
         href: https://emby.vogt.de.com/
         description: Emby
+        widget:
+          type: emby
+          url: https://emby.vogt.de.com
+          key: "{{HOMEPAGE_VAR_EMBY_KEY}}"
+          enableBlocks: true
+          enableNowPlaying: true
 
     - Sonarr:
         icon: sonarr.svg
@@ -462,3 +468,8 @@
         icon: overseerr.svg
         href: https://os.vogt.de.com
         description: Seerr
+        widget:
+          type: seerr
+          url: https://os.vogt.de.com
+          key: "{{HOMEPAGE_VAR_SEERR_KEY}}"
+          fields: ["pending", "approved", "completed"]