fix(glob): fix typo that caused patterns like .*/* to escape cwd boundary (#24939)

## Summary

- Fixed a typo in `makeComponent` that incorrectly identified
2-character patterns starting with `.` (like `.*`) as `..` (DotBack)
patterns
- The condition checked `pattern[component.start] == '.'` twice instead
of checking both characters at positions 0 and 1
- This caused patterns like `.*/*` to be parsed as `../` + `*`, making
the glob walker traverse into parent directories

Fixes #24936

## Test plan

- [x] Added tests in `test/js/bun/glob/scan.test.ts` that verify
patterns like `.*/*` and `.*/**/*.ts` don't escape the cwd boundary
- [x] Tests fail with system bun (bug reproduced) and pass with the fix
- [x] All existing glob tests pass (169 tests)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>

src/glob/GlobWalker.zig

@@ -1431,12 +1431,12 @@ pub fn GlobWalker_(
             if (component.len == 0) return null;
 
             out: {
-                if (component.len == 1 and pattern[component.start] == '.') {
+                if (bun.strings.eqlComptime(pattern[component.start .. component.start + component.len], ".")) {
                     component.syntax_hint = .Dot;
                     has_relative_patterns.* = true;
                     break :out;
                 }
-                if (component.len == 2 and pattern[component.start] == '.' and pattern[component.start] == '.') {
+                if (bun.strings.eqlComptime(pattern[component.start .. component.start + component.len], "..")) {
                     component.syntax_hint = .DotBack;
                     has_relative_patterns.* = true;
                     break :out;

test/js/bun/glob/scan.test.ts

@@ -665,6 +665,78 @@ describe("absolute path pattern", async () => {
   });
 });
 
+// https://github.com/oven-sh/bun/issues/24936
+describe("glob scan should not escape cwd boundary", () => {
+  test("pattern .*/* should not match parent directory via ..", async () => {
+    // Create a directory structure where we can verify paths don't escape cwd
+    const tempdir = tempDirWithFiles("glob-cwd-escape", {
+      ".hidden": {
+        "file.txt": "hidden file content",
+      },
+      ".dotfile": "dot file",
+      "regular": {
+        "file.txt": "regular file",
+      },
+    });
+
+    const glob = new Glob(".*/*");
+    const entries = await Array.fromAsync(
+      glob.scan({
+        cwd: tempdir,
+        onlyFiles: false,
+        dot: true, // Need dot:true to match dotfiles/directories
+      }),
+    );
+
+    // All entries should be within the cwd - none should start with ../
+    for (const entry of entries) {
+      expect(entry.startsWith("../")).toBe(false);
+      expect(entry.startsWith("..\\")).toBe(false);
+      expect(entry.includes("/../")).toBe(false);
+      expect(entry.includes("\\..\\")).toBe(false);
+    }
+
+    // Should match .hidden/file.txt but not escape to parent
+    expect(entries.sort()).toEqual([`.hidden${path.sep}file.txt`].sort());
+  });
+
+  test("pattern .*/**/*.ts should not escape cwd", async () => {
+    const tempdir = tempDirWithFiles("glob-cwd-escape-ts", {
+      ".config": {
+        "settings.ts": "export default {}",
+        "nested": {
+          "deep.ts": "export const x = 1",
+        },
+      },
+      "src": {
+        "index.ts": "console.log('hi')",
+      },
+    });
+
+    const glob = new Glob(".*/**/*.ts");
+    const entries = await Array.fromAsync(
+      glob.scan({
+        cwd: tempdir,
+        onlyFiles: true,
+        dot: true, // Need dot:true to match dotfiles/directories
+      }),
+    );
+
+    // All entries should be within the cwd
+    for (const entry of entries) {
+      expect(entry.startsWith("../")).toBe(false);
+      expect(entry.startsWith("..\\")).toBe(false);
+      expect(entry.includes("/../")).toBe(false);
+      expect(entry.includes("\\..\\")).toBe(false);
+    }
+
+    // Should match files in .config but not escape to parent
+    expect(entries.sort()).toEqual(
+      [`.config${path.sep}settings.ts`, `.config${path.sep}nested${path.sep}deep.ts`].sort(),
+    );
+  });
+});
+
 describe("glob.scan wildcard fast path", async () => {
   test("works", async () => {
     const tempdir = tempDirWithFiles("glob-scan-wildcard-fast-path", {