Fix Android reader scan edge cases

[djwok]

Summary

• Use the Bluetooth address when an Android scan result has no advertised or cached Reader name.
• Reject the active scan when ACS Reader creation fails instead of silently dropping the result.

Root cause

The single filtered BLE scan path returned early for nameless results and swallowed ACS factory exceptions, leaving callers with missing Readers and no actionable failure.

Validation

• pnpm lint
• pnpm build
• pnpm test -- --runInBand --no-watchman