refactor(deps): migrate dotenv from v16.5.0 to v17.3.1

[s0wa48]

Changes

Breaking Change: dotenv v17 is ESM-only

dotenv v17 dropped legacy CommonJS interop. The import dotenv from 'dotenv'; dotenv.config() pattern still works in TypeScript/ESM contexts, but the recommended idiomatic approach is now to use the dotenv/config side-effect import which automatically loads .env on import.

Migrations applied

• package.json: Bumped dotenv from ^16.5.0 to ^17.3.1
• validator/index.ts: Replaced import dotenv from 'dotenv' + dotenv.config() call with the simpler import 'dotenv/config' side-effect import
• scripts/weights.ts: Replaced import dotenv from 'dotenv' + dotenv.config() with import 'dotenv/config'
• scripts/create-key.ts: Replaced import dotenv from 'dotenv' + dotenv.config() with import 'dotenv/config'
• hardhat.config.js: Added safe wrapper around require('dotenv') call since this file runs as CommonJS in Hardhat context; dotenv v17's ESM-first design requires careful handling in CJS environments

Notes

• The dotenv/config import pattern is the v17-recommended approach and works seamlessly with TypeScript and bundlers
• The .env file path and override option in hardhat.config.js are preserved as-is since that file has custom path resolution logic

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