fix: address PR review comments

- Fix KV json overload to return Promise<unknown | null> (null on missing keys)
- Add shebang to Husky pre-commit hook
- Explicitly add eslint ^10.0.0 to devDependencies

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.husky/pre-commit

@@ -1 +1,2 @@
+#!/bin/sh
 npx lint-staged && npm run typecheck && npm test

package.json

@@ -32,6 +32,7 @@
     "@types/mailparser": "^3.4.6",
     "@types/rss": "^0.0.32",
     "@vitest/coverage-v8": "^4.0.18",
+    "eslint": "^10.0.0",
     "eslint-config-prettier": "^10.1.8",
     "happy-dom": "^20.5.0",
     "husky": "^9.1.7",

src/types/index.ts

@@ -71,7 +71,7 @@ declare global {
   // This is not an ideal solution but works for our example
   interface KVNamespace {
     get(key: string, options?: { type: "text" }): Promise<string | null>;
-    get(key: string, options: { type: "json" }): Promise<unknown>;
+    get(key: string, options: { type: "json" }): Promise<unknown | null>;
     get(
       key: string,
       options: { type: "arrayBuffer" },