初始提交：terminalX 可运行态（M0/M1/M1.5 已真机验证）

- M0: libghostty SSH 终端（渲染/输入/连接）+ 白屏修复(OutputGate) + 会话状态机/自动重连
- M1: tsnet 用户态组网 + SSH-over-tsnet(fd 桥)，shell 级真机验证；R5(Go+gvisor+C+++Swift 同进程) retire
- M1.5: tmux -CC 原生 tab（MVP）
- 结构: packages/(TXCore·TXTransport), apps/TerminalX, vendor/(libghostty-spm/libssh2/mbedtls/tsnet-bridge), artifacts/
- 文档: CLAUDE.md + docs/HANDOFF.md（新会话入口）
- 环境: 认证代理→依赖 vendor 本地化；Go 在 ~/.local/go；仅模拟器/未签名
- 待续: M2 mosh, tmux 多 pane, M4 安全(host key/SE)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

vendor/libghostty-spm/Tests/GhosttyKitTest/TerminalMarkedTextStateTests.swift

@@ -0,0 +1,48 @@
+import Foundation
+@testable import GhosttyTerminal
+import Testing
+
+struct TerminalMarkedTextStateTests {
+    @Test
+    func `delete backward removes selection before caret`() {
+        var state = TerminalMarkedTextState()
+        state.setMarkedText("shufa", selectedRange: NSRange(location: 5, length: 0))
+        let deleted = state.deleteBackward()
+
+        #expect(deleted)
+        #expect(state.text == "shuf")
+        #expect(state.selectedRange == NSRange(location: 4, length: 0))
+        #expect(state.currentSelectedRange == NSRange(location: 4, length: 0))
+    }
+
+    @Test
+    func `delete backward clears single marked character`() {
+        var state = TerminalMarkedTextState()
+        state.setMarkedText("字", selectedRange: NSRange(location: 1, length: 0))
+        let deleted = state.deleteBackward()
+
+        #expect(deleted)
+        #expect(state.text == nil)
+        #expect(state.markedRange == NSRange(location: NSNotFound, length: 0))
+        #expect(state.currentSelectedRange == NSRange(location: NSNotFound, length: 0))
+    }
+
+    @Test
+    func `set marked text clamps selection into document`() {
+        var state = TerminalMarkedTextState()
+        state.setMarkedText("abcd", selectedRange: NSRange(location: 99, length: 3))
+
+        #expect(state.selectedRange == NSRange(location: 4, length: 0))
+        #expect(state.documentLength == 4)
+    }
+
+    @Test
+    func `text in range returns substring and empty caret slice`() {
+        var state = TerminalMarkedTextState()
+        state.setMarkedText("中文abc", selectedRange: NSRange(location: 2, length: 0))
+
+        #expect(state.text(in: NSRange(location: 0, length: 2)) == "中文")
+        #expect(state.text(in: NSRange(location: 2, length: 0)) == "")
+        #expect(state.text(in: NSRange(location: 99, length: 1)) == nil)
+    }
+}