(new): expand runtime APIs

(fix): harden concurrent lifecycle
(tests): add regression coverage
(doc): update v1.2 guidance

tgrich/build_test.go

@@ -216,6 +216,13 @@ func TestBuildHTMLLimits(t *testing.T) {
 		{"combined nesting too deep", func() []tgapi.InputRichBlock {
 			return []tgapi.InputRichBlock{P(wrapBold(Text("text"), maxRichDepth))}
 		}, ErrRichNestingTooDeep},
+		{"rich text arrays too deep", func() []tgapi.InputRichBlock {
+			text := tgapi.RichText(Text("text"))
+			for range maxRichDepth {
+				text = tgapi.RichTextArray{text}
+			}
+			return []tgapi.InputRichBlock{P(text)}
+		}, ErrRichNestingTooDeep},
 		{"maximum block nesting", func() []tgapi.InputRichBlock {
 			return []tgapi.InputRichBlock{wrapDetails(P(Text("text")), maxRichDepth-1)}
 		}, nil},