switch to unixshells/vt-go, ungate framebuffer for WASM

- Replace charmbracelet/x/vt with unixshells/vt-go (IRM support)
- Remove ultraviolet import from framebuffer.go (use local attr constants)
- Framebuffer compiles for all platforms including js/wasm
- WASM build requires -tags osusergo for os/user compatibility

framebuffer.go

@@ -1,5 +1,3 @@
-//go:build !js
-
 package mosh
 
 import (
@@ -7,9 +5,18 @@ import (
 	"strconv"
 	"unicode/utf8"
 
-	uv "github.com/charmbracelet/ultraviolet"
 	"github.com/charmbracelet/x/ansi"
-	"github.com/charmbracelet/x/vt"
+	"github.com/unixshells/vt-go"
+)
+
+// Cell attribute bitmasks (matching charmbracelet/ultraviolet values).
+const (
+	attrBold          = 1 << 0
+	attrFaint         = 1 << 1
+	attrItalic        = 1 << 2
+	attrBlink         = 1 << 3
+	attrReverse       = 1 << 4
+	attrStrikethrough = 1 << 5
 )
 
 // Framebuffer represents a terminal screen state for mosh SSP.
@@ -403,13 +410,13 @@ func SnapshotEmulator(emu *vt.Emulator, cursorVisible bool) *Framebuffer {
 			}
 
 			// Attributes.
-			cell.Attr.Bold = c.Style.Attrs&uv.AttrBold != 0
-			cell.Attr.Dim = c.Style.Attrs&uv.AttrFaint != 0
-			cell.Attr.Italic = c.Style.Attrs&uv.AttrItalic != 0
-			cell.Attr.Blink = c.Style.Attrs&uv.AttrBlink != 0
-			cell.Attr.Reverse = c.Style.Attrs&uv.AttrReverse != 0
-			cell.Attr.Strike = c.Style.Attrs&uv.AttrStrikethrough != 0
-			cell.Attr.Under = c.Style.Underline != uv.UnderlineNone
+			cell.Attr.Bold = c.Style.Attrs&attrBold != 0
+			cell.Attr.Dim = c.Style.Attrs&attrFaint != 0
+			cell.Attr.Italic = c.Style.Attrs&attrItalic != 0
+			cell.Attr.Blink = c.Style.Attrs&attrBlink != 0
+			cell.Attr.Reverse = c.Style.Attrs&attrReverse != 0
+			cell.Attr.Strike = c.Style.Attrs&attrStrikethrough != 0
+			cell.Attr.Under = c.Style.Underline != ansi.UnderlineNone
 
 			cell.Attr.FG = convertColor(c.Style.Fg)
 			cell.Attr.BG = convertColor(c.Style.Bg)

go.mod

@@ -3,16 +3,16 @@ module github.com/unixshells/mosh-go
 go 1.26.0
 
 require (
-	github.com/charmbracelet/ultraviolet v0.0.0-20260303162955-0b88c25f3fff
 	github.com/charmbracelet/x/ansi v0.11.6
-	github.com/charmbracelet/x/vt v0.0.0-20260305213658-fe36e8c10185
 	github.com/creack/pty v1.1.24
+	github.com/unixshells/vt-go v0.1.0
 	golang.org/x/crypto v0.49.0
 	golang.org/x/term v0.41.0
 )
 
 require (
 	github.com/charmbracelet/colorprofile v0.4.2 // indirect
+	github.com/charmbracelet/ultraviolet v0.0.0-20260303162955-0b88c25f3fff // indirect
 	github.com/charmbracelet/x/exp/ordered v0.1.0 // indirect
 	github.com/charmbracelet/x/term v0.2.2 // indirect
 	github.com/charmbracelet/x/termios v0.1.1 // indirect

go.sum

@@ -10,8 +10,6 @@ github.com/charmbracelet/x/term v0.2.2 h1:xVRT/S2ZcKdhhOuSP4t5cLi5o+JxklsoEObBSg
 github.com/charmbracelet/x/term v0.2.2/go.mod h1:kF8CY5RddLWrsgVwpw4kAa6TESp6EB5y3uxGLeCqzAI=
 github.com/charmbracelet/x/termios v0.1.1 h1:o3Q2bT8eqzGnGPOYheoYS8eEleT5ZVNYNy8JawjaNZY=
 github.com/charmbracelet/x/termios v0.1.1/go.mod h1:rB7fnv1TgOPOyyKRJ9o+AsTU/vK5WHJ2ivHeut/Pcwo=
-github.com/charmbracelet/x/vt v0.0.0-20260305213658-fe36e8c10185 h1:KYS9lWBROkdkuyc0bdQuS8C86Me3OAgjUAKcB4zArlg=
-github.com/charmbracelet/x/vt v0.0.0-20260305213658-fe36e8c10185/go.mod h1:2djWW5EeP5QlpztEYYbbyyzUyyxVD71mWVQguNISHcM=
 github.com/charmbracelet/x/windows v0.2.2 h1:IofanmuvaxnKHuV04sC0eBy/smG6kIKrWG2/jYn2GuM=
 github.com/charmbracelet/x/windows v0.2.2/go.mod h1:/8XtdKZzedat74NQFn0NGlGL4soHB0YQZrETF96h75k=
 github.com/clipperhouse/displaywidth v0.9.0 h1:Qb4KOhYwRiN3viMv1v/3cTBlz3AcAZX3+y9OLhMtAtA=
@@ -30,6 +28,8 @@ github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELU
 github.com/muesli/cancelreader v0.2.2/go.mod h1:3XuTXfFS2VjM+HTLZY9Ak0l6eUKfijIfMUZ4EgX0QYo=
 github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
 github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
+github.com/unixshells/vt-go v0.1.0 h1:HWILcExV8MHc6o2YqIRMIM/KrjH31kPzZrlvLS9BG6Y=
+github.com/unixshells/vt-go v0.1.0/go.mod h1:dZpOXxVyO7LG1uxkVMixX7HwUf2ZbUkEKhtHHJTTIBI=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
 github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
 golang.org/x/crypto v0.49.0 h1:+Ng2ULVvLHnJ/ZFEq4KdcDd/cfjrrjjNSXNzxg0Y4U4=

server.go

@@ -15,7 +15,7 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/charmbracelet/x/vt"
+	"github.com/unixshells/vt-go"
 	"github.com/creack/pty"
 )