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).

file_es_text_integration_test.go

@@ -52,7 +52,7 @@ func TestIntegrationESTextIndex(t *testing.T) {
 	token := "gotes" + stamp
 	doc := TextDoc{
 		ID:       "3578",
-		Title:    "2026-07-28-S1021-Edelweiss-rechnung.pdf",
+		Title:    "2026-07-28-S1021-acme-rechnung.pdf",
 		FolderID: "634",
 		Ext:      "pdf",
 		Content:  "Begleitzettel SGB XI — Rechnung " + token,