chore: keep host/client specifics out of the tree (env & config)

Showroom-safe: the tree no longer carries internal hosts, IPs, ports,
personal names, client domains or client file names. Behaviour is
unchanged and now supplied per deployment.

- catalog: hardcoded mail-org / project classifiers become a YAML-driven
  Classifier (OO_CATALOG_CONFIG or --config); neutral default classifies
  nothing as work. New catalog/classify.go + example + tests.
- storage_fallback: drop the baked-in MinIO endpoint IP; require
  MINIO_ENDPOINT (+ keys) from the env.
- kontolink: build DocEditor links from $ONLYOFFICE_URL instead of a
  hardcoded portal host; kontoblatt: no client file id in the output name.
- oo: load .env CLI-wide (bootstrap.LoadEnv in execute) so
  non-authenticating commands (catalog scans) also see config.
- genericize comments/docs/fixtures (AGENTS, README, .env.example,
  crm-associations, catalog tests, ES/pdfattach tests, mails).

docs/crm-associations.md

@@ -120,5 +120,5 @@ oo mails draft-invoice --invoice INVOICE_ID --to billing@example.com
 ## Related
 
 - README § invoices / mail / CRM cleanup  
-- Personal workspace tooling (disk inventory, dossier sync): private
-  `git.produktor.io/eSlider/oo-workspace` (`oow` CLI)
+- Personal workspace tooling (disk inventory, dossier sync) lives in a private
+  companion repo (`oo-workspace`, the `oow` CLI).