sx-gitea Phase 1: repo — forge core (owners, repo CRUD, per-repo git stores) + dream browse views (TDD, 91/91)

lib/gitea/repo.sx: forge handle over persist kv; owner principals
(user/org directory, identity-backed in Phase 2); repo records with
visibility/default-branch metadata; per-repo sx-git namespaces
(forge/<owner>/<name>) so delete is a prefix purge; ref resolution
(branch/tag/cid, annotated tags peeled) and tree-path navigation.

lib/gitea/web.sx: dream routes — repo index, repo home, branches,
tree/blob/raw browse at any ref, commit log, single-commit diff view,
JSON API for repo create/list/delete (201/400/409 semantics).

lib/gitea/tests/repo.sx (91 tests) + conformance.sh + scoreboard.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

lib/gitea/scoreboard.json

@@ -0,0 +1,8 @@
+{
+  "suites": {
+    "repo": {"pass": 91, "fail": 0}
+  },
+  "total_pass": 91,
+  "total_fail": 0,
+  "total": 91
+}