feat: real EXIF extraction via adapters-exif crate

- MetadataExtractorPort in domain (bytes → StructuredData)
- adapters-exif: NomExifExtractor using nom-exif, handles EXIF + TrackInfo
- Worker's MetadataExtractorPlugin delegates to port, no longer knows nom-exif
- Filters noisy binary tags (U8Array, Undefined, Unknown)

crates/domain/src/catalog/ports.rs

@@ -3,8 +3,9 @@ use super::entities::{
     MetadataSource,
 };
 use crate::common::errors::DomainError;
-use crate::common::value_objects::{Checksum, SystemId};
+use crate::common::value_objects::{Checksum, StructuredData, SystemId};
 use async_trait::async_trait;
+use bytes::Bytes;
 
 // --- AssetRepository ---
 
@@ -74,3 +75,9 @@ pub trait DuplicateRepository: Send + Sync {
     async fn find_by_asset(&self, asset_id: &SystemId) -> Result<Vec<DuplicateGroup>, DomainError>;
     async fn save(&self, group: &DuplicateGroup) -> Result<(), DomainError>;
 }
+
+// --- MetadataExtractorPort ---
+
+pub trait MetadataExtractorPort: Send + Sync {
+    fn extract(&self, bytes: &Bytes) -> Result<StructuredData, DomainError>;
+}