feat: version list with verification + deployed badge (stage 3)

- pulp_client: list_versions / list_distributions / get_publication
- GET /repos/{uuid}/versions: 버전 목록 페이지(최신순)
- 현재 운영 배포 버전 판별: Distribution→publication→repository_version 역추적
- views.build_version_view: vN, 생성일시, 패키지 수, 증감(+/-), 검증 배지, 배포 여부
- views.verification_detail: gpgcheck/repo-gpgcheck/checksum 상세 (화면4)
- 대시보드 저장소명 → 버전 페이지 링크, [이 버전 배포] 버튼은 단계4용 placeholder
- 단계1 TODO(배포 버전 역추적) 해소

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/routes/versions.py

@@ -0,0 +1,78 @@
+"""버전(스냅샷) 목록 + 검증 배지 (화면 3 전반).
+
+GET /repos/{uuid}/versions → 해당 저장소의 RepositoryVersion 목록 페이지(최신순).
+
+현재 운영 배포 버전은 Distribution → publication → repository_version 역추적으로 판별한다
+(스펙 §4). 배포 버튼 활성화/확인은 단계 4에서 연결.
+"""
+
+from __future__ import annotations
+
+import httpx
+from fastapi import APIRouter, Depends, Request
+from fastapi.responses import HTMLResponse
+
+from .. import views
+from ..deps import get_pulp_client, templates
+from ..pulp_client import PulpClient
+
+router = APIRouter()
+
+
+def _deployed_version_number(pulp: PulpClient, uuid: str) -> int | None:
+    """이 저장소가 현재 운영 배포 중인 버전 번호. 없거나 조회 실패 시 None.
+
+    Distribution.publication → Publication.repository_version 이 이 저장소의
+    버전을 가리키면 그 번호를 반환.
+    """
+    needle = f"/repositories/rpm/rpm/{uuid}/versions/"
+    try:
+        distributions = pulp.list_distributions()
+    except httpx.HTTPError:
+        return None
+
+    for dist in distributions:
+        pub_href = dist.get("publication")
+        if not pub_href:
+            continue  # repository 직접 배포(최신 추종)는 단계4 TODO
+        try:
+            pub = pulp.get_publication(pub_href)
+        except httpx.HTTPError:
+            continue
+        rv = pub.get("repository_version") or ""
+        if needle in rv:
+            return views.version_number(rv)
+    return None
+
+
+@router.get("/repos/{uuid}/versions", response_class=HTMLResponse)
+def versions(
+    request: Request, uuid: str, pulp: PulpClient = Depends(get_pulp_client)
+) -> HTMLResponse:
+    try:
+        repo = pulp.get_repo(uuid)
+        raw_versions = pulp.list_versions(uuid)
+    except httpx.HTTPError as exc:
+        return templates.TemplateResponse(
+            request,
+            "versions.html",
+            {"repo_name": uuid, "uuid": uuid, "error": str(exc)},
+        )
+
+    gpg = views.gpg_status(repo)
+    deployed = _deployed_version_number(pulp, uuid)
+    version_views = [views.build_version_view(v, deployed, gpg) for v in raw_versions]
+    version_views.sort(key=lambda v: v["number"] or 0, reverse=True)  # 최신순
+
+    return templates.TemplateResponse(
+        request,
+        "versions.html",
+        {
+            "repo_name": repo.get("name", uuid),
+            "uuid": uuid,
+            "versions": version_views,
+            "verification": views.verification_detail(repo),
+            "deployed": deployed,
+            "error": None,
+        },
+    )