Rename the web app from FatihsMG4 to Nils' MG4

Browser title, login heading, hidden password-manager username, session
cookie (nilsmg4_session) and package name. The README keeps the credit
to fatihdonmezdev/FatihsMG4. Server version 1.1.1; the manifests pin it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QLJfZQZeAKAwSqViTmLzki

k8s/kustomization.yaml

@@ -9,4 +9,4 @@ resources:
   - ingress.yaml
 images:
   - name: git.stinnesbeck.com/nils/mg4-server
-    newTag: "1.1.0"
+    newTag: "1.1.1"