Refactor insights handling and error encoding in presentation layer

- Updated insights analyzer tests to use Utc for date handling.
- Added timezone support for insights retrieval, allowing insights to be bucketed by the user's local time.
- Introduced `encode_domain_error` for better error handling in API responses.
- Modified various handlers to utilize the new error encoding function.
- Enhanced insights API to reject unknown time zones and return appropriate errors.
- Updated frontend components to handle insights data with timezone awareness.
- Improved localization for insights sample counts.

crates/presentation/Cargo.toml

@@ -26,6 +26,7 @@ tokio = { workspace = true }
 dotenvy = { workspace = true }
 uuid = { workspace = true }
 chrono = { workspace = true }
+chrono-tz = { workspace = true }
 async-trait = { workspace = true }
 futures = { workspace = true }