Declare export compliance for TestFlight tag builds

[enaboapps]

Summary

• write ITSAppUsesNonExemptEncryption=false into the generated native Info.plist before archiving
• preserve exact release-tag application source while applying the reviewed TestFlight compliance metadata
• retain the existing post-export assertion so a missing declaration still blocks upload

Tracks #90.

Evidence

Run 32645876747 archived and exported successfully, then safely stopped before upload because the Beta 11 tag predates the Expo compliance declaration.

Validation

• git diff --check
• Node 24 npm run validate (43 suites / 312 tests; Expo Doctor 21/21)

[enaboapps]

Independent latest-head review completed for 686834c: no actionable findings. The review confirmed the post-prebuild plist path, Boolean mutation behavior for both existing and absent keys, Bash failure semantics, and retention of the post-export upload gate.