Summary

• add hasna.provider_live_mode_standard.v1 to the contracts schema registry
• document provider/live-mode safety requirements for sandbox/read-only/live-mutating surfaces
• add valid/invalid examples and schema/example coverage

Validation

• bun install
• bun test tests/schemas.test.ts tests/examples.test.ts
• bun run typecheck
• bun run conformance
• bun test
• bun run build
• bun run verify:release
• staged secrets scan: todos redaction scan --file /tmp/worker3-provider-standard-staged.diff

Coordination

This PR is the provider/live-mode standard base for Worker 2's contracts PR #8. Worker 3 did not edit infra service/deployment contract surfaces. If PR #8 lands first, this branch must be retargeted/rebased; preferred order is land this provider-standard PR first, then rebase/land PR #8.