fix(OSS/TOP): OSS is normative root, not a tenant/legal entity

- LEGAL_ENTITY.v7g.json: OSS reframed as normative root (kind: normative_root,
  parent: null, legalForm removed). Maintainer block added pointing to GCC
  (GitCover Commons gUG) as the legal entity maintaining the root. GCC's real
  company repos live on git.gitcover.de (not public .org).
- others.json: tenant key -> root; legal_form null; maintained_by -> GCC.
- README.md / README.en.md / dictionaries/README.md: "OSS-Tenant" ->
  "OSS (normative Root)" throughout; OSS clarified as no-parent normative root
  maintained by GCC, not a legal entity.
- Spec (GITCOVER_PROTOCOL) and GCP.Questionnaire ADR-003 references updated
  in their respective working trees.

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

.gitcover/others.json

@@ -1,9 +1,11 @@
 {
   "v7g_version": "1.0",
-  "tenant": {
+  "root": {
     "id": "oss-top",
-    "name": "GitCover OSS Commons — TOP (zentrale Dictionary-Heimat)",
-    "legal_form": "gUG",
+    "name": "GitCover OSS — normative Root (TOP: zentrale Dictionary-Heimat)",
+    "kind": "normative_root",
+    "legal_form": null,
+    "maintained_by": { "shortCode": "GCC", "legalForm": "gUG", "registeredName": "GitCover Commons gUG (haftungsbeschränkt)" },
     "repository_id": 1,
     "role": "normative_registry",
     "group": "gitcover",
@@ -34,6 +36,6 @@
     "normative": true,
     "exchange": ["gcep", "gcucb"],
     "hosted": ["kinds.json", "status_flags.json"],
-    "note": "L1-L6-Dictionaries verbleiben vorerst im CFP-Tenant (Konsolidierung in OSS = Folge-Slice)."
+    "note": "L1-L6-Dictionaries verbleiben vorerst im CFP-Tenant (Konsolidierung in den OSS-Normative-Root = Folge-Slice)."
   }
 }