install: make the debug-build stack dump on package install failure opt-in

src/install/PackageInstaller.rs

@@ -2197,10 +2197,13 @@ impl<'a> PackageInstaller<'a> {
                                 ),
                             ),
                         );
+                        // Opt-in: ordinary failures; the dump would land in the install output.
                         #[cfg(bun_debug)]
-                        {
-                            let t = cause.debug_trace;
-                            bun_crash_handler::dump_stack_trace(&t.trace(), Default::default());
+                        if PackageInstaller.is_visible() {
+                            bun_crash_handler::dump_stack_trace(
+                                &cause.debug_trace.trace(),
+                                Default::default(),
+                            );
                         }
                         self.summary.fail += 1;
                     }

test/cli/install/bun-link.test.ts

@@ -458,7 +458,13 @@ it("should link dependency without crashing", async () => {
     env,
   });
   const err4 = await new Response(stderr4).text();
-  expect(err4).toContain(`FileNotFound: failed linking dependency/workspace to node_modules for package ${link_name}`);
+  // Debug builds used to follow this line with a stack trace (on stdout via
+  // llvm-symbolizer on Linux, on stderr elsewhere); neither stream may carry it
+  // unless BUN_DEBUG_PackageInstaller=1 is set.
+  expect(err4.split(/\r?\n/)).toEqual([
+    `FileNotFound: failed linking dependency/workspace to node_modules for package ${link_name}`,
+    "",
+  ]);
   const out4 = await new Response(stdout4).text();
   expect(out4.replace(/\[[0-9\.]+m?s\]/, "[]").split(/\r?\n/)).toEqual([
     expect.stringContaining("bun install v1."),