feat(api): expose async backup/restore job status (fixes #7)

Backup and restore only enqueue a cluster Job; a later failure left its
only trace in that Job object, invisible without kubectl. Add
GET /api/v1/servers/{name}/jobs (owner-or-admin) projecting the newest
20 managed Jobs (felis-backup / felis-restore) as
running|succeeded|failed with message and timestamps. Nil reader -> 503
jobs_unavailable, mirroring the backup/restore feature gates. RBAC gains
jobs:list; OpenAPI parity updated.

internal/platform/rbac.go

@@ -97,7 +97,9 @@ func APIMinecraftRole(p Params) *rbacv1.Role {
 	return role(p.MinecraftNamespace, "felis-api", ComponentAPI, []rbacv1.PolicyRule{
 		rule([]string{groupFelis}, []string{"minecraftservers"}, []string{"get", "list", "create", "patch"}),
 		rule([]string{groupCore}, []string{"secrets"}, []string{"get"}),
-		rule([]string{groupBatch}, []string{"jobs"}, []string{"create", "get", "delete"}),
+		// list backs GET /servers/{name}/jobs — the async status outlet reads the
+		// backup/restore Jobs back by the server label (read-only).
+		rule([]string{groupBatch}, []string{"jobs"}, []string{"create", "get", "delete", "list"}),
 		// Read-side console (spec §8 读=pods/log follow): list pods to find the
 		// server's running pod, then read its log subresource. Two separate rules so
 		// the verbs stay tight — list on pods, get on pods/log, and nothing else.