feat: Implement advanced filtering with new filter conditions and a strategy-based query builder.

libertas_core/src/schema.rs

@@ -59,6 +59,7 @@ pub struct SortParams {
 pub struct FilterParams {
     pub mime_type: Option<String>,
     pub metadata_filters: Option<Vec<MetadataFilter>>,
+    pub conditions: Option<Vec<FilterCondition>>,
     // In the future, we can add fields like:
     // pub date_range: Option<(chrono::DateTime<chrono::Utc>, chrono::DateTime<chrono::Utc>)>,
 }
@@ -82,6 +83,24 @@ pub struct MetadataFilter {
     pub tag_value: String,
 }
 
+#[derive(Debug, Clone)]
+pub struct FilterCondition {
+    pub field: String,
+    pub operator: FilterOperator,
+    pub value: String,
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum FilterOperator {
+    Eq,
+    Neq,
+    Like,
+    Gt,
+    Lt,
+    Gte,
+    Lte,
+}
+
 pub struct MediaImportBundle {
     pub media_model: Media,
     pub metadata_models: Vec<MediaMetadata>,