fix: add missing DECRPM mode responses for permanently set/reset and dynamic modes

Add cases to privateModeSetting and ansiModeSetting for modes that
upstream xterm.js reports but the Go port returned NOT_RECOGNIZED:

ANSI modes:
- Mode 2 (KAM): permanently reset
- Mode 12 (SRM): permanently set

DEC private modes:
- Mode 8 (DECARM): permanently set
- Mode 12 (cursor blink): dynamic based on CursorBlink option
- Mode 67 (DECBKM): permanently reset
- Mode 1005 (UTF-8 mouse): permanently reset
- Mode 1015 (urxvt mouse): permanently reset
- Mode 1048 (save cursor): always set

Fixes #27
Fixes #28

Co-authored-by: Ona <no-reply@ona.com>

Author: ona-automations

inputhandler_csi.go

@@ -776,12 +776,18 @@ func (h *InputHandler) privateModeSetting(mode int) int {
 		return boolToPm(dm.Origin)
 	case 7:
 		return boolToPm(dm.Wraparound)
+	case 8:
+		return 3 // DECARM: permanently set
+	case 12:
+		return boolToPm(h.optionsService.Options.CursorBlink)
 	case 25:
 		return boolToPm(!h.coreService.IsCursorHidden)
 	case 45:
 		return boolToPm(dm.ReverseWraparound)
 	case 66:
 		return boolToPm(dm.ApplicationKeypad)
+	case 67:
+		return 4 // DECBKM: permanently reset
 	case 9:
 		return boolToPm(dm.MouseTrackingMode == "X10")
 	case 1000:
@@ -792,10 +798,16 @@ func (h *InputHandler) privateModeSetting(mode int) int {
 		return boolToPm(dm.MouseTrackingMode == "ANY")
 	case 1004:
 		return boolToPm(dm.SendFocus)
+	case 1005:
+		return 4 // UTF-8 mouse: permanently reset
 	case 1006:
 		return boolToPm(dm.MouseEncoding == "SGR")
+	case 1015:
+		return 4 // urxvt mouse: permanently reset
 	case 1016:
 		return boolToPm(dm.MouseEncoding == "SGR_PIXELS")
+	case 1048:
+		return 1 // save cursor: always set
 	case 47, 1047, 1049:
 		return boolToPm(h.bufferService.Buffers.Active() == h.bufferService.Buffers.Alt())
 	case 2004:
@@ -814,8 +826,12 @@ func (h *InputHandler) privateModeSetting(mode int) int {
 // ansiModeSetting returns the DECRPM Pm value for an ANSI mode.
 func (h *InputHandler) ansiModeSetting(mode int) int {
 	switch mode {
+	case 2:
+		return 4 // KAM: permanently reset
 	case 4:
 		return boolToPm(h.coreService.Modes.InsertMode)
+	case 12:
+		return 3 // SRM: permanently set
 	case 20:
 		return boolToPm(h.optionsService.Options.ConvertEol)
 	default:

inputhandler_csi_test.go

@@ -1217,6 +1217,14 @@ func TestRequestModePrivate(t *testing.T) {
 		{"mouse_encoding_sgr", "\x1b[?1006h", "\x1b[?1006$p", "\x1b[?1006;1$y"},
 		{"color_scheme_updates_set", "\x1b[?2031h", "\x1b[?2031$p", "\x1b[?2031;1$y"},
 		{"win32_input_set", "\x1b[?9001h", "\x1b[?9001$p", "\x1b[?9001;1$y"},
+		// Permanently set/reset modes (issue #27)
+		{"DECARM_permanently_set", "", "\x1b[?8$p", "\x1b[?8;3$y"},
+		{"DECBKM_permanently_reset", "", "\x1b[?67$p", "\x1b[?67;4$y"},
+		{"UTF8_mouse_permanently_reset", "", "\x1b[?1005$p", "\x1b[?1005;4$y"},
+		{"urxvt_mouse_permanently_reset", "", "\x1b[?1015$p", "\x1b[?1015;4$y"},
+		// Dynamic mode reports (issue #28)
+		{"cursor_blink_default_reset", "", "\x1b[?12$p", "\x1b[?12;2$y"},
+		{"save_cursor_always_set", "", "\x1b[?1048$p", "\x1b[?1048;1$y"},
 	}
 	for _, tc := range tests {
 		t.Run(tc.Name, func(t *testing.T) {
@@ -1248,6 +1256,9 @@ func TestRequestModeANSI(t *testing.T) {
 		{"insert_mode_default", "", "\x1b[4$p", "\x1b[4;2$y"},
 		{"insert_mode_set", "\x1b[4h", "\x1b[4$p", "\x1b[4;1$y"},
 		{"convert_eol_default", "", "\x1b[20$p", "\x1b[20;2$y"},
+		// Permanently set/reset modes (issue #27)
+		{"KAM_permanently_reset", "", "\x1b[2$p", "\x1b[2;4$y"},
+		{"SRM_permanently_set", "", "\x1b[12$p", "\x1b[12;3$y"},
 		{"unrecognized_ansi_mode", "", "\x1b[99$p", "\x1b[99;0$y"},
 	}
 	for _, tc := range tests {
@@ -1269,6 +1280,33 @@ func TestRequestModeANSI(t *testing.T) {
 	}
 }
 
+func TestRequestModeCursorBlinkEnabled(t *testing.T) {
+	t.Parallel()
+	// CursorBlink enabled should report SET (Pm=1) for mode 12.
+	opts := DefaultOptions()
+	opts.Cols = 80
+	opts.Rows = 24
+	opts.Scrollback = 1000
+	opts.CursorBlink = true
+	optsSvc := NewOptionsService(&opts)
+	bufSvc := NewBufferService(optsSvc)
+	charSvc := NewCharsetService()
+	coreSvc := NewCoreService(optsSvc)
+	oscLinkSvc := NewOscLinkService(bufSvc)
+	uniSvc := NewUnicodeService()
+	h := NewInputHandler(bufSvc, charSvc, coreSvc, optsSvc, oscLinkSvc, uniSvc)
+
+	var response string
+	h.coreService.OnDataEmitter.Event(func(data string) {
+		response = data
+	})
+	h.ParseString("\x1b[?12$p")
+	expected := "\x1b[?12;1$y"
+	if response != expected {
+		t.Errorf("expected response %q, got %q", expected, response)
+	}
+}
+
 func TestWindowOptionsReportSize(t *testing.T) {
 	t.Parallel()
 	h := newTestInputHandler(80, 24)