Add Team perpetual license support

[NghiaTranUIT]

Summary

• add Team perpetual license activation with Ed25519-signed receipts
• keep Standard, Combo, and Lifetime on the existing unsigned activation and verification flow
• store Team activation credentials in Keychain and enforce device, build, offline-deadline, and clock checks
• add recovery actions for seat limits, renewal, revocation, disabled licenses, and app updates
• add synthetic cross-language receipt fixtures and focused unit coverage

Compatibility

• existing Standard, Combo, and Lifetime activations remain valid after updating the app
• fresh activations for those plans do not require the receipt signing key
• only Team activations require signed receipts and the embedded public key

Security

• the app contains only the receipt verification public key
• the matching private signing key remains in ignored backend-only storage with mode 0600
• fixtures contain no real license keys, customer data, or device identifiers

Testing

• focused TCPViewer license tests: 39 passed across 4 suites
• TCPViewer scheme build: passed
• git diff --check: passed

AI assistance

This pull request was substantially assisted by OpenAI Codex. The contributor reviewed and tested the changes and takes responsibility for them.