Enforce commercial account readiness gates

[oratis]

What changed

• require verified Instagram Professional-account eligibility
• distinguish LinkedIn member and organization targets
• require an organization-role check for LinkedIn organization publishing
• require a verified Facebook Page role
• add fail-closed readiness tests for every new account-level gate

Why

The original #327 profiles documented these external gates but readiness could still return ready without proving them, overstating production capability.

Validation

• node --import tsx --test src/sense/social/connectors/commercial.test.ts
• npm run typecheck
• npm test
• npm run build
• npm run check:api-contract
• git diff --check