List the missing channel modes in the 004 reply (closes #238)

The channel-modes parameter of RPL_MYINFO left out modes that each
transport's MODE accepts. The IRC listener now sends Himnostv, adding
H, i, o and v. The HTTP API now sends Hbiklmnostv, adding H, b and v.
Each transport keeps its own list, because they accept different
modes. The tests compare the whole parameter, so a missing or extra
mode fails them. The README and the schema notes show the new HTTP API
list.

Model: opus-5-5

internal/handlers/api_test.go

@@ -6797,9 +6797,10 @@ func TestISUPPORT(t *testing.T) {
 	}
 }
 
-// TestMyInfoListsUserModes verifies the 004 numeric lists
-// the user modes o and w as its third parameter.
-func TestMyInfoListsUserModes(t *testing.T) {
+// TestMyInfoListsModes verifies the 004 numeric lists the
+// user modes o and w as its third parameter, and the HTTP
+// API's channel modes Hbiklmnostv as its fourth.
+func TestMyInfoListsModes(t *testing.T) {
 	t.Parallel()
 
 	tserver := newTestServer(t)
@@ -6813,9 +6814,10 @@ func TestMyInfoListsUserModes(t *testing.T) {
 	}
 
 	params := getNumericParams(myInfo)
-	if len(params) != 4 || params[2] != "ow" {
+	if len(params) != 4 || params[2] != "ow" ||
+		params[3] != "Hbiklmnostv" {
 		t.Fatalf(
-			"004 params %v, want four with user modes ow third",
+			"004 params %v, want four ending ow Hbiklmnostv",
 			params,
 		)
 	}