feat: optional topology per rack

- New topology option "Umfang": whole network (per site) and/or per
  rack, one landscape page each. Rack pages are grouped under
  "Topologie je Rack" with the rack titles one heading level lower to
  keep the table of contents short.
- Directly connected devices outside the rack are shown dimmed and
  dashed with their rack as subtitle, so uplinks stay visible.
- Cable paths are collected once per export and reused for all views.

Fix: devices from other sites were able to pull in their own neighbors
as external nodes; only direct neighbors of a group's devices are shown
now.

Bump version to 0.8.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

netbox_customer_export/__init__.py

@@ -5,7 +5,7 @@ class CustomerExportConfig(PluginConfig):
     name = "netbox_customer_export"
     verbose_name = "Kunden-Export"
     description = "Kundendokumentation als PDF oder Word exportieren"
-    version = "0.7.0"
+    version = "0.8.0"
     author = "Claude"
     base_url = "customer-export"
     min_version = "4.6.8"