fix(sourcemap): remove incorrect tab character exemption in scalar path

Fixes #22003

The scalar fallback path in IndexOfNeedsEscapeForJavaScriptStringImpl had
`(char_ < 0x20 && char_ != 0x09)` which incorrectly exempted tab characters
(0x09) from escaping. This created an inconsistency with the SIMD path which
correctly detects tabs as needing escape (since tab < 0x20).

While tabs would typically be caught by the SIMD path in most cases, this
inconsistency could cause issues when tabs appear in the small remainder
portion after SIMD processing, leading to invalid JSON in sourcemaps.

The fix removes the `&& char_ != 0x09` exemption, ensuring tabs are always
properly detected as needing escape in both SIMD and scalar code paths.

src/bun.js/bindings/highway_strings.cpp

@@ -482,7 +482,7 @@ static size_t IndexOfNeedsEscapeForJavaScriptStringImpl(const uint8_t* HWY_RESTR
     // Scalar check for the remainder
     for (; i < text_len; ++i) {
         const uint8_t char_ = text[i];
-        if (char_ >= 127 || (char_ < 0x20 && char_ != 0x09) || char_ == '\\' || char_ == quote_char || (is_backtick && char_ == '$')) {
+        if (char_ >= 127 || char_ < 0x20 || char_ == '\\' || char_ == quote_char || (is_backtick && char_ == '$')) {
             return i;
         }
     }

test/regression/issue/22003.test.ts

@@ -0,0 +1,59 @@
+import { describe, expect, test } from "bun:test";
+import { bunEnv, bunExe, tempDir } from "harness";
+
+// https://github.com/oven-sh/bun/issues/22003
+describe("sourcemap escaping with tab characters - issue #22003", () => {
+  test("tabs in source should be properly escaped in sourcemap JSON", async () => {
+    using dir = tempDir("22003", {
+      "index.js": `module.exports = {\n\th32: require("./a"),\n\th64: require("./b")\n};`,
+      "a.js": "module.exports = 'a';",
+      "b.js": "module.exports = 'b';",
+    });
+
+    await using proc = Bun.spawn({
+      cmd: [bunExe(), "build", "index.js", "--outfile=out.js", "--sourcemap"],
+      env: bunEnv,
+      cwd: String(dir),
+      stderr: "pipe",
+    });
+
+    const [stderr, exitCode] = await Promise.all([proc.stderr.text(), proc.exited]);
+
+    expect(exitCode).toBe(0);
+    expect(stderr).not.toContain("InvalidSourceMap");
+
+    const sourcemapContent = await Bun.file(`${dir}/out.js.map`).text();
+
+    // Must be valid JSON
+    let sourcemap;
+    expect(() => {
+      sourcemap = JSON.parse(sourcemapContent);
+    }).not.toThrow();
+
+    // sourcesContent should have the tab properly escaped
+    expect(sourcemap.sourcesContent).toBeDefined();
+    const indexSource = sourcemap.sourcesContent.find((s: string) => s.includes("h32") && s.includes("h64"));
+    expect(indexSource).toBeDefined();
+    // When parsed from JSON, \t becomes actual tab character
+    expect(indexSource).toContain("\th32");
+    expect(indexSource).toContain("\th64");
+  });
+
+  test("tabs with --compile should not cause InvalidSourceMap error", async () => {
+    using dir = tempDir("22003-compile", {
+      "index.js": `// Comment with tab:\there\nconsole.log("test");`,
+    });
+
+    await using proc = Bun.spawn({
+      cmd: [bunExe(), "build", "index.js", "--compile", "--sourcemap", "--outfile=out.exe"],
+      env: bunEnv,
+      cwd: String(dir),
+      stderr: "pipe",
+    });
+
+    const [stderr, exitCode] = await Promise.all([proc.stderr.text(), proc.exited]);
+
+    expect(exitCode).toBe(0);
+    expect(stderr).not.toContain("InvalidSourceMap");
+  });
+});