refactor: extract shared sandbox and gateway plumbing

src/auto-reply/reply/reply-inline-whitespace.test.ts

@@ -0,0 +1,9 @@
+import { describe, expect, it } from "vitest";
+import { collapseInlineHorizontalWhitespace } from "./reply-inline-whitespace.js";
+
+describe("collapseInlineHorizontalWhitespace", () => {
+  it("collapses spaces and tabs but preserves newlines", () => {
+    const value = "hello\t\tworld\n  next\tline";
+    expect(collapseInlineHorizontalWhitespace(value)).toBe("hello world\n next line");
+  });
+});

src/auto-reply/reply/reply-inline-whitespace.ts

@@ -0,0 +1,5 @@
+const INLINE_HORIZONTAL_WHITESPACE_RE = /[^\S\n]+/g;
+
+export function collapseInlineHorizontalWhitespace(value: string): string {
+  return value.replace(INLINE_HORIZONTAL_WHITESPACE_RE, " ");
+}

src/auto-reply/reply/reply-inline.ts

@@ -1,3 +1,5 @@
+import { collapseInlineHorizontalWhitespace } from "./reply-inline-whitespace.js";
+
 const INLINE_SIMPLE_COMMAND_ALIASES = new Map<string, string>([
   ["/help", "/help"],
   ["/commands", "/commands"],
@@ -24,10 +26,7 @@ export function extractInlineSimpleCommand(body?: string): {
   if (!command) {
     return null;
   }
-  const cleaned = body
-    .replace(match[0], " ")
-    .replace(/[^\S\n]+/g, " ")
-    .trim();
+  const cleaned = collapseInlineHorizontalWhitespace(body.replace(match[0], " ")).trim();
   return { command, cleaned };
 }
 
@@ -41,9 +40,6 @@ export function stripInlineStatus(body: string): {
   }
   // Use [^\S\n]+ instead of \s+ to only collapse horizontal whitespace,
   // preserving newlines so multi-line messages keep their paragraph structure.
-  const cleaned = trimmed
-    .replace(INLINE_STATUS_RE, " ")
-    .replace(/[^\S\n]+/g, " ")
-    .trim();
+  const cleaned = collapseInlineHorizontalWhitespace(trimmed.replace(INLINE_STATUS_RE, " ")).trim();
   return { cleaned, didStrip: cleaned !== trimmed };
 }