add zod and fix types

[Jovian-Dsouza]

Fixes Zod dependency issue and install required types for weather-typescript-server

Motivation and Context

Solves #22

> tsc && node -e "require('fs').chmodSync('build/index.js', '755')"

src/index.ts:3:19 - error TS2307: Cannot find module 'zod' or its corresponding type declarations.

3 import { z } from "zod";
                    ~~~~~

src/index.ts:89:23 - error TS18046: 'state' is of type 'unknown'.

89     const stateCode = state.toUpperCase();
                         ~~~~~

src/index.ts:143:49 - error TS18046: 'latitude' is of type 'unknown'.

143     const pointsUrl = `${NWS_API_BASE}/points/${latitude.toFixed(4)},${longitude.toFixed(4)}`;
                                                    ~~~~~~~~

src/index.ts:143:72 - error TS18046: 'longitude' is of type 'unknown'.

143     const pointsUrl = `${NWS_API_BASE}/points/${latitude.toFixed(4)},${longitude.toFixed(4)}`;   

How Has This Been Tested?

Yes

Breaking Changes

No

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

[cundejo]

LGTM

[Jovian-Dsouza]

Still need approvals for merging the changes

[hongshikkim-libertylabs]

FYI, if you install zod 4 server stops without any message. install zod 3 as this PR did