fix: harden Windows trans helpers

Resolve #1691 by preserving argv boundaries, adding bounded native rg and wc/skill query support, surfacing WSL-to-Windows hints, and splitting the oversized SSH module and embedded remote scripts.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/src/gh-body-input.test.ts

@@ -0,0 +1,33 @@
+import { spawnSync } from "node:child_process";
+import { describe, expect, test } from "bun:test";
+
+describe("gh Markdown stdin", () => {
+  test("preserves backticks, dollar expressions, and heredoc markers byte-for-byte", () => {
+    const body = [
+      "目标合并分支: 不适用",
+      "",
+      "`G14` 与 $HOME 保持原样。",
+      "",
+      "<<'INNER'",
+      "markdown `code` ${literal}",
+      "INNER",
+      "",
+    ].join("\n");
+    const script = [
+      'import { readMarkdownBodyFileOrStdin } from "./scripts/src/gh/body-input.ts";',
+      'process.stdout.write(JSON.stringify(readMarkdownBodyFileOrStdin("-")));',
+    ].join(" ");
+    const result = spawnSync(process.execPath, ["-e", script], {
+      cwd: process.cwd(),
+      input: body,
+      encoding: "utf8",
+    });
+
+    expect(result.status).toBe(0);
+    expect(result.stderr).toBe("");
+    expect(JSON.parse(result.stdout)).toEqual({
+      body,
+      bodySource: { kind: "stdin", path: "-" },
+    });
+  });
+});