chore: fix lint errors and reduce warnings across codebase (#234)

* chore: fix lint errors and reduce warnings across codebase

- Fix noExplicitAny catches in backend routes and plugins
- Fix noNestedTernary issues in backend services
- Add keyboard event handlers for useKeyWithClickEvents in frontend
- Disable noImportantStyles rule in biome.json
- Fix formatting errors across all changed files
- Fix test file lint issues

Closes #233

* fix: restore any types in test files for TS compatibility

* fix: revert Auth.tsx dependency array changes that caused infinite re-render

* fix: null-safe user.username access in AppContext dependency array

frontend/src/components/DateTimeInput.tsx

@@ -29,7 +29,13 @@ export function DateTimeInput({ value, placeholder, className, ...rest }: DateTi
 	}, []);
 
 	return (
-		<div className={`date-input-wrapper ${className ?? ""}`} onClick={handleClick}>
+		<div
+			className={`date-input-wrapper ${className ?? ""}`}
+			onClick={handleClick}
+			onKeyDown={(e) => {
+				if (e.key === "Enter" || e.key === " ") handleClick();
+			}}
+		>
 			<span className="date-input-display" aria-hidden="true">
 				{displayValue || placeholder || ""}
 			</span>