fix: Ensure Promise rejection reasons are Error objects

- Replace unsafe 'as Error' cast with proper type guard
- Enable noImplicitReturns and useUnknownInCatchVariables for stricter type checking
- Fixes TypeScript ESLint prefer-promise-reject-errors rule compliance

Author: Hi7cl4w

src/test/suite/index.ts

@@ -34,7 +34,7 @@ export function run(): Promise<void> {
         });
       } catch (err) {
         console.error(err);
-        e(err as Error);
+        e(err instanceof Error ? err : new Error(String(err)));
       }
     });
   });

tsconfig.json

@@ -5,9 +5,10 @@
     "lib": ["ES2020"],
     "sourceMap": true,
     "rootDir": "src",
-    "strict": true /* enable all strict type-checking options */
+    "strict": true /* enable all strict type-checking options */,
     /* Additional Checks */
-    // "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
+    "noImplicitReturns": true /* Report error when not all code paths in function return a value. */,
+    "useUnknownInCatchVariables": true /* Type caught variables as 'unknown' instead of 'any' */
     // "noFallthroughCasesInSwitch": true, /* Report errors for fallthrough cases in switch statement. */
     // "noUnusedParameters": true,  /* Report errors on unused parameters. */
   }