refactor: move Helm chart to standard directory structure

This commit restructures the paperless-ai Helm chart by moving all files
 from the nested directory (charts/paperless-ai/paperless-ai/) to the
 standard Helm chart directory structure (charts/paperless-ai/). The change
 eliminates the redundant directory nesting that was causing issues with
 Helm chart packaging and installation. No functional changes were made to
 any files - this is purely a directory structure reorganization to follow
 Helm best practices and improve chart maintainability.

charts/paperless-ai/templates/paperlessApiSecret.yaml

@@ -0,0 +1,11 @@
+{{- if .Values.paperless.apiToken }}
+apiVersion: v1
+kind: Secret
+metadata:
+  name: {{ include "paperless-ai.fullname" . }}-paperless-api
+  labels:
+    {{- include "paperless-ai.labels" . | nindent 4 }}
+type: Opaque
+data:
+  PAPERLESS_API_TOKEN: {{ .Values.paperless.apiToken  | b64enc | quote }}
+{{- end }}