test(kiro): clear the platform store between seeds, not just the macOS one

Second ubuntu failure from the same lidge-jun#718 family, surfaced by the first fix
turning five failures into one.

`inspectKiroCliSqlite distinguishes token_missing and invalid_json` seeds a
database, asserts, then re-seeds to exercise the invalid-JSON branch. Its
mid-test cleanup removed only `$tmp/Library`, which is the macOS store. On
Linux the database lives at `.local/share/kiro-cli`, so it survived and the
second seed hit `SQLiteError: table auth_kv already exists`.

Removing `kiroCliDbDir()` instead follows the platform, exactly as the seeding
side already did. Confirmed the asymmetry: a Library-only removal covers the
darwin store and neither the win32 nor the linux one.

Gates: tsc clean; kiro-oauth + kiro-windows-cli-db-path 57 pass 0 fail.

Author: lidge-jun

tests/kiro-oauth.test.ts

@@ -654,7 +654,10 @@ describe("kiro oauth — import-first", () => {
     expect(missing.token).toBeNull();
     expect(missing.diagnostics).toContainEqual({ location: kiroCliDbLocation(), status: "token_missing" });
 
-    rmSync(join(tmp, "Library"), { recursive: true, force: true });
+    // Drop the seeded database before re-seeding. This has to follow the platform: removing only
+    // `Library` left the Linux store at `.local/share` in place, so the second seed hit
+    // "table auth_kv already exists" and the case failed on ubuntu CI while passing on macOS (#718).
+    rmSync(kiroCliDbDir(), { recursive: true, force: true });
     seedKiroCliRawValue("{not json");
 
     const invalid = inspectKiroCliSqlite();