* fix: correct flag emoji for ISO alpha-3 region code
* fix: use rust_iso3166 to convert ISO3 region code
* fix: validate ISO country code when generating flag emoji
* fix: correct icon encoding for unlock test in specific regions
---------
Co-authored-by: Tunglies <77394545+Tunglies@users.noreply.github.com>
- Split the monolithic unlock checker into a module tree (mod.rs:9–133), wiring service-specific tasks while keeping exported Tauri commands untouched.
- Centralize shared data and helpers in types.rs (1–40) and utils.rs (1–21) for reusable timestamp and emoji logic.
- Move each provider’s logic into its own file (bilibili.rs, disney_plus.rs, netflix.rs, etc.), preserving behavior and making future additions or fixes localized.
