fix: support bracket notation for env var replacement in Vite define

[RobSchilderr]

Problem

Vite's define config performs literal text replacement on source code. The clientEnvDefine object in loadEnv.ts currently only generates dot-notation keys:

`process.env.${key}`
`import.meta.env.${key}`

This means bracket notation access — which is common in TypeScript codebases where noPropertyAccessFromIndexSignature is enabled — is never replaced and resolves to undefined at runtime:

// ✅ Works — replaced by Vite
process.env.ONE_PUBLIC_POSTHOG_KEY

// ❌ Broken — not replaced, becomes undefined
process.env["ONE_PUBLIC_POSTHOG_KEY"]

TypeScript's noPropertyAccessFromIndexSignature compiler option (part of strict configs) requires bracket notation for index signatures, which makes process.env["KEY"] the natural way to access env vars. This creates a subtle bug where env vars silently resolve to undefined in client bundles.

Fix

Add bracket-notation entries (both double and single quotes) to the clientEnvDefine output for both process.env and import.meta.env:

return [
  [`process.env.${key}`, stringified],
  [`process.env["${key}"]`, stringified],
  [`process.env['${key}']`, stringified],
  [`import.meta.env.${key}`, stringified],
  [`import.meta.env["${key}"]`, stringified],
  [`import.meta.env['${key}']`, stringified],
]

Note: Metro's Babel plugin (import-meta-env-plugin.ts) already handles both notations via AST analysis, so this only affects the Vite/web path.