Add user-first Bloom docs section

[violet-agent]

Summary

• adds a first-class Use Bloom docs area adapted from the Non-tech Docs Google Doc for user-first onboarding
• adds a plain-English Concepts page for sandbox, plan, outbox, policy, petals, and self-custody
• restructures the sidebar so users come first, followed by product model, integrator setup, wallet reference, technical reference, and petal developer docs
• updates the homepage to route the three audiences explicitly: users, integrators, and developers
• preserves the alpha/unaudited/mainnet-off warning and removes source-doc-only notes/comments

Notes

• Source was exported from the provided Google Doc through Google Drive.
• Claude Code reviewed the PR after initial publication; follow-up feedback was incorporated in a second commit (docs: incorporate Claude review feedback).

Verification

• claude -p --max-turns 20 --add-dir /tmp/bloom-docs-source < /tmp/bloom-docs-claude-review.txt
• npm run lint
• npm run build
• preview smoke-tested /, /use-bloom/concepts/, and /use-bloom/quickstart/ locally with browser console clean

[cloudflare-workers-and-pages]

Deploying bloom-docs with    Cloudflare Pages

Latest commit:	28845b2
Status:	✅  Deploy successful!
Preview URL:	https://7785f456.bloom-docs-ezr.pages.dev
Branch Preview URL:	https://docs-non-tech-first.bloom-docs-ezr.pages.dev

View logs