fix: resolve all lint errors across source and test files

- Fix unused function parameters (prefix with _)
- Fix unused imports in test files
- Fix import ordering in test files
- Auto-fix formatting issues across 22 files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/server/routes/items.ts

@@ -114,5 +114,4 @@ app.delete("/:id", async (c) => {
 	return c.json({ success: true });
 });
 
-
 export { app as itemRoutes };