chore: move business tooling out of the public library; tidy filestore naming

Keep the public tree project-generic. Business/one-off tools, deployment
and business docs move to the private oo-workspace repo.

Moved to oo-workspace:
- cmd/ooscan, cmd/pdfamount, cmd/kontoblatt, cmd/kontolink
- internal/xlspipe (cutover-portugal workbook) -> oow workbook build
  (drops the --template/--title flags from oo docs put-xlsx)
- deploy/docker-compose.rclone-webdav.yml + docs/rclone-webdav.md
- docs/crm-associations.md

Removed GitHub-era leftovers:
- .github/workflows/release-please.yml, release-please-config.json,
  .release-please-manifest.json (tags are created on Gitea per SemVer)

Naming: the FileStore subsystem is now filestore_*.go (was file_*.go) to
match files_*.go (project Documents). Docs/AGENTS/README updated.

cmd/oo/main.go

@@ -22,7 +22,7 @@
 //	oo search        QUERY [--content] [--folder ID] [--limit N] [--backend oo|own] [--json]
 //	oo index         folder FOLDER_ID | files FILE_ID... [--recursive] [--exts pdf] [--dry-run]
 //
-// CRM association rules: docs/crm-associations.md
+// CRM association rules live with the private oo-workspace tooling.
 //
 // Every list supports `--output/-o json|table` (table is the default).
 //