docs(privacy): document provider data boundaries

[iannuttall]

Summary

• document every current outbound data boundary across Google, DataForSEO, Semrush, Bing, IndexNow, CrUX, crawling, telemetry, and agent clients
• explain the explicit Search Console enrichment boundary and list what is never sent to a research provider
• align the README, legal pages, setup and provider guides, cookie and telemetry copy, and the packaged SEO skill
• remove the stale version number from the illustrative README help output
• state the current reset and provider-keychain deletion behavior accurately

Verification

• pnpm build
• pnpm typecheck
• pnpm test
• pnpm lint
• pnpm security:check
• pnpm pack --dry-run
• official external policy links return HTTP 200
• 71 report ids, 71 eval files, 32 report surfaces, and one packaged skill remain in sync

Follow-up

The audit found that seo reset --yes does not remove DataForSEO, Bing, or IndexNow secrets stored in the operating-system keychain. This PR documents the current behavior accurately. The runtime reset fix stays separate so this remains a docs-only change.