feat: rename product to EnvSift

[devchaudhary24k]

What changed

• rename the product from EnvKit to EnvSift across application metadata, documentation, manifest, SEO, and product planning
• keep lowercase envsift for URLs, slugs, package names, and identifiers
• change the canonical site URL to https://envsift.damnlabs.com
• update expected GitHub links to pixelactstudio/envsift
• update analytics URL fixtures without changing the privacy boundary

Validation

• pnpm test
• pnpm typecheck
• pnpm lint
• pnpm check
• pnpm build
• stale-brand casing scan
• git diff --check

Note

Rename product from EnvKit to EnvSift across the codebase

Updates all branding references from EnvKit to EnvSift, including site config, PWA manifest, SEO meta tags, analytics test URLs, and documentation. Risk: the theme storage key changes from envkit-theme to envsift-theme, so previously saved theme preferences will be lost.

^{Macroscope summarized c918e42.}

[cloudflare-workers-and-pages]

Deploying envkit with    Cloudflare Pages

Latest commit:	c918e42
Status:	✅  Deploy successful!
Preview URL:	https://53372ec1.envkit.pages.dev
Branch Preview URL:	https://codex-rename-envsift.envkit.pages.dev

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