Give every team a page of its own

The Admin tab's team list was growing controls the way the user list did
before ac9af8e: a Rename button behind window.prompt, a Delete beside it,
and -- on the Users page, of all places -- an invite form with a team
picker in front of it. The picker was the admission that an invite is a
fact about a team rather than about the server, and a prompt() is the
wrong place to read a 409 about a name already taken.

So a team is now a subject with a page, at /admin/teams/{id}, the mirror
of /admin/users/{id}: when it was created, how many are in it and how
much is open, a field to rename it, the members with their roles, the
invites into it, and deletion. The list goes back to being a list, and
the name in it is the way in.

The member list is the one thing there that needed a new endpoint.
GET /api/teams/{id}/members is requireTeamMember and answers 404 to an
administrator who is not in the team, and that stays exactly as it is:
member means membership and nothing else. Reading a team's shape is a
different question from reading its work, so it gets an endpoint of its
own under AdminOnly -- GET /api/admin/teams/{id}, returning
{"team", "members"} -- rather than an exception carved into that rule. It
is a wrapper and not a team with the members hung off it, because
"members" already means a count on the list endpoint and one name must
not be a number in one answer and an array in the next. The query and its
ordering are copied from handleListTeamMembers so the two answers to "who
is in this team" cannot disagree.

An administrator still sees none of that team's incidents, alerts or
rota. Nothing about what the flag may do changed; it could already rename
and delete any team, and staff one it is not in.

Rename now trims what it is given, as creation has always trimmed. Before
this, " " was a legal name to rename a team to but not to create one
with, which is one rule stated twice and applied once.

Nobody has looked at this in a browser, the caveat ac9af8e and 07914d5
both carried. What is checked is the wiring: admin_test.go covers the new
endpoint for an administrator outside the team, the 404 the member-only
endpoint still gives that same administrator, the 403 for a member who is
not one, a 404 for a team that does not exist, a 400 for an id that is not
a number, and the trim; the module graph evaluates at /admin/teams/{id},
and the server serves index.html there, so a reload survives.

Claude-Session: https://claude.ai/code/session_01RHPj4ggeFdEjKKfm4SHbD7

internal/api/admin_test.go

@@ -310,6 +310,127 @@ func TestAdmin_ConfiguresATeamTheyAreNotIn(t *testing.T) {
 	}
 }
 
+// The team page at /admin/teams/{id} needs the one question the test above
+// leaves shut: who is in a team the administrator is not in.
+//
+// It is answered by a separate endpoint under AdminOnly rather than by letting
+// the admin flag through requireTeamMember, and the second half of this test is
+// the reason — /api/teams/{id}/members must keep answering 404, so that "member
+// means membership and nothing else" stays true of the endpoint it was said
+// about. Reading a team's shape and reading a team's work are different things.
+func TestAdminGetTeam_ReadsAnyTeamWithoutJoiningIt(t *testing.T) {
+	s := newTS(t)
+
+	founderID, call := member(t, s, "founder")
+	var team struct {
+		ID int64 `json:"id"`
+	}
+	decode(t, call(http.MethodPost, "/api/teams", map[string]string{"name": "theirs"}), &team)
+	if team.ID == 0 {
+		t.Fatal("no team was created")
+	}
+
+	// The admin reads it whole, without being in it.
+	var got struct {
+		Team struct {
+			ID            int64  `json:"id"`
+			Name          string `json:"name"`
+			Members       int64  `json:"members"`
+			OpenIncidents int64  `json:"open_incidents"`
+		} `json:"team"`
+		Members []struct {
+			UserID   int64  `json:"user_id"`
+			Username string `json:"username"`
+			Role     string `json:"role"`
+		} `json:"members"`
+	}
+	decode(t, s.req(t, http.MethodGet, "/api/admin/teams/"+id64(team.ID), nil), &got)
+
+	if got.Team.ID != team.ID || got.Team.Name != "theirs" {
+		t.Errorf("expected team %d named theirs, got %d named %q", team.ID, got.Team.ID, got.Team.Name)
+	}
+	if got.Team.Members != 1 {
+		t.Errorf("expected a member count of 1, got %d", got.Team.Members)
+	}
+	if len(got.Members) != 1 {
+		t.Fatalf("expected one member, got %d", len(got.Members))
+	}
+	if got.Members[0].UserID != founderID || got.Members[0].Username != "founder" {
+		t.Errorf("expected founder (%d), got %q (%d)",
+			founderID, got.Members[0].Username, got.Members[0].UserID)
+	}
+	// Whoever creates a team owns it, and the page's role toggle depends on
+	// that being reported rather than assumed.
+	if got.Members[0].Role != "owner" {
+		t.Errorf("expected the creator to be owner, got %q", got.Members[0].Role)
+	}
+
+	// The rule this endpoint exists in order not to break. Same admin, same
+	// team, the member-only endpoint: still not found.
+	resp := s.req(t, http.MethodGet, "/api/teams/"+id64(team.ID)+"/members", nil)
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusNotFound {
+		t.Errorf("an admin outside the team must still get 404 from the member-only list, got %d",
+			resp.StatusCode)
+	}
+
+	// And the new one is administration, not membership: being in the team is
+	// not enough.
+	resp = call(http.MethodGet, "/api/admin/teams/"+id64(team.ID), nil)
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusForbidden {
+		t.Errorf("a non-admin member must get 403, got %d", resp.StatusCode)
+	}
+
+	for _, c := range []struct {
+		name string
+		path string
+		want int
+	}{
+		{"a team that does not exist", "/api/admin/teams/999999", http.StatusNotFound},
+		{"a team id that is not a number", "/api/admin/teams/nonsense", http.StatusBadRequest},
+	} {
+		resp := s.req(t, http.MethodGet, c.path, nil)
+		resp.Body.Close()
+		if resp.StatusCode != c.want {
+			t.Errorf("%s: expected %d, got %d", c.name, c.want, resp.StatusCode)
+		}
+	}
+}
+
+// A team name is trimmed when it is created, and renaming had not been, so " "
+// was a legal name to rename to and an illegal one to start with.
+func TestRenameTeam_TrimsTheName(t *testing.T) {
+	s := newTS(t)
+	var team struct {
+		ID int64 `json:"id"`
+	}
+	decode(t, s.req(t, http.MethodPost, "/api/teams", map[string]string{"name": "trimmed"}), &team)
+
+	path := "/api/teams/" + id64(team.ID)
+	resp := s.req(t, http.MethodPut, path, map[string]string{"name": "   "})
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusBadRequest {
+		t.Errorf("a blank name must be refused, got %d", resp.StatusCode)
+	}
+
+	resp = s.req(t, http.MethodPut, path, map[string]string{"name": "  padded  "})
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusNoContent {
+		t.Fatalf("expected 204, got %d", resp.StatusCode)
+	}
+
+	var got struct {
+		Team struct {
+			Name string `json:"name"`
+		} `json:"team"`
+	}
+	decode(t, s.req(t, http.MethodGet, "/api/admin/teams/"+id64(team.ID), nil), &got)
+	if got.Team.Name != "padded" {
+		t.Errorf("expected the name to be trimmed to %q, got %q", "padded", got.Team.Name)
+	}
+}
+
 // The admin page's per-user view asks what somebody is in. Self or admin, like
 // the rest of the per-user endpoints.
 func TestUserTeams_SelfOrAdmin(t *testing.T) {