feat: add unified mobile measurement api

[KingDoxik]

Summary

• add a unified React Native measurement, links, consent, notification, purchase, and diagnostic API
• add durable iOS and Android collection, storage, delivery, retry, privacy, and configuration support
• add protected evidence, signed links, attribution domains, generated clients, self-host configuration, integration doctor, and documentation
• add parity, load, failure, native, contract, and migration coverage

Why

Mobile attribution and lifecycle evidence need one policy-aware API and a durable delivery contract that remains correct across offline use, retries, process death, and self-hosted deployments.

Impact

Applications gain namespaced measurement capabilities, signed invite and deferred-link flows, protected identifiers and purchase evidence, native push/link collection, endpoint overrides, and auditable diagnostics. Existing analytics and purchase behavior remains supported through the unified runtime.

Validation

• React Native: 245 tests passed
• Core: 1,289 tests passed
• Backend: 169 tests passed
• Swift: 27 tests passed
• Android: 14 tests passed
• database migration integration test passed
• TypeScript checks passed for affected packages
• Nitro and OpenAPI generation completed
• git diff --check passed

[github-actions]

Thank you for following the naming conventions for pull request titles! 🙏

[KingDoxik]

Superseded by #115 after the branch rename.