fix(apiserver): enforce self_ug job scopes and accept project filters (bug-1934, bug-1935)

bug-1934: every job-permission check read a single scope and compared it
only with "self", so a job:view or job:control grant scoped to self_ug acted
like "all" (list, get by ID, control), and self + self_ug collapsed to self.
userJobScope() now collects all of a user's grants of a job permission
before deduplication and adds them up (all; self; self_ug = the user and
everyone sharing a user group). The job list appends a submit_user filter
for narrower scopes, get-by-ID keeps covered rows in a new slice (removing
from the ranged slice skipped rows) and answers 403, both control paths
and job output check the owner against the scope. User groups now reach
the apiserver: the config push converts cluster_config_t.ugroups and
OnUserGroupsUpdated() replaces the new store (nested groups, all,
exclusions). The default basic_user now also sees its user-group mates'
jobs, as its configuration says.

bug-1935: project_name and license_project are accepted job filters, so
xcecli jobs list -P works.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/frontend/apiserver/backend/convert.go

@@ -250,6 +250,42 @@ func cHostConfigToModel(hc *C.xce_hostconfig_t) *models.HostInfo {
 	})
 }
 
+// cStrList converts an xce_strlist_t to a Go slice.
+func cStrList(l *C.xce_strlist_t) []string {
+	n := int(l.count)
+	if n == 0 || l.data == nil {
+		return nil
+	}
+	out := make([]string, 0, n)
+	for _, p := range unsafe.Slice(l.data, n) {
+		if p != nil {
+			out = append(out, C.GoString(p))
+		}
+	}
+	return out
+}
+
+// cClusterConfUserGroups extracts the user groups from a cluster_config_t
+// (bug-1934: the self_ug job scope resolves them).
+func cClusterConfUserGroups(conf *C.cluster_config_t) []models.UserGroupInfo {
+	n := int(conf.nugroups)
+	if n == 0 || conf.ugroups == nil {
+		return nil
+	}
+	out := make([]models.UserGroupInfo, 0, n)
+	for _, gp := range unsafe.Slice(conf.ugroups, n) {
+		if gp == nil || gp.name == nil {
+			continue
+		}
+		out = append(out, models.UserGroupInfo{
+			Name:      C.GoString(gp.name),
+			Members:   cStrList(&gp.members),
+			ExMembers: cStrList(&gp.ex_members),
+		})
+	}
+	return out
+}
+
 // cClusterConfHostConfigs extracts host config models from a cluster_config_t.
 func cClusterConfHostConfigs(conf *C.cluster_config_t) []models.HostInfo {
 	n := int(conf.nhconfigs)