Add wildcard and multi-value support for tag/search filters (#18)

- Tag filters now support wildcards (*) converted to SQL LIKE (%)
- Tag filters now support comma-separated multiple values
- Applied to /api/v1/artifacts, /api/v1/tags, and /api/v1/uploads endpoints

backend/app/routes.py

@@ -2593,7 +2593,10 @@ def list_package_artifacts(
 def list_all_artifacts(
     project: Optional[str] = Query(None, description="Filter by project name"),
     package: Optional[str] = Query(None, description="Filter by package name"),
-    tag: Optional[str] = Query(None, description="Filter by tag name"),
+    tag: Optional[str] = Query(
+        None,
+        description="Filter by tag name. Supports wildcards (*) and comma-separated values",
+    ),
     content_type: Optional[str] = Query(None, description="Filter by content type"),
     min_size: Optional[int] = Query(None, ge=0, description="Minimum size in bytes"),
     max_size: Optional[int] = Query(None, ge=0, description="Maximum size in bytes"),
@@ -2628,7 +2631,26 @@ def list_all_artifacts(
         if package:
             tag_query = tag_query.filter(Package.name == package)
         if tag:
-            tag_query = tag_query.filter(Tag.name == tag)
+            # Support multiple values (comma-separated) and wildcards (*)
+            tag_values = [t.strip() for t in tag.split(",") if t.strip()]
+            if len(tag_values) == 1:
+                tag_val = tag_values[0]
+                if "*" in tag_val:
+                    # Wildcard: convert * to SQL LIKE %
+                    tag_query = tag_query.filter(
+                        Tag.name.ilike(tag_val.replace("*", "%"))
+                    )
+                else:
+                    tag_query = tag_query.filter(Tag.name == tag_val)
+            else:
+                # Multiple values: check if any match (with wildcard support)
+                tag_conditions = []
+                for tag_val in tag_values:
+                    if "*" in tag_val:
+                        tag_conditions.append(Tag.name.ilike(tag_val.replace("*", "%")))
+                    else:
+                        tag_conditions.append(Tag.name == tag_val)
+                tag_query = tag_query.filter(or_(*tag_conditions))
         artifact_ids = tag_query.distinct().subquery()
         query = query.filter(Artifact.id.in_(artifact_ids))
 
@@ -2722,7 +2744,10 @@ def list_all_artifacts(
 def list_all_tags(
     project: Optional[str] = Query(None, description="Filter by project name"),
     package: Optional[str] = Query(None, description="Filter by package name"),
-    search: Optional[str] = Query(None, description="Search by tag name"),
+    search: Optional[str] = Query(
+        None,
+        description="Search by tag name. Supports wildcards (*) and comma-separated values",
+    ),
     from_date: Optional[datetime] = Query(
         None, alias="from", description="Created after"
     ),
@@ -2749,7 +2774,24 @@ def list_all_tags(
     if package:
         query = query.filter(Package.name == package)
     if search:
-        query = query.filter(Tag.name.ilike(f"%{search}%"))
+        # Support multiple values (comma-separated) and wildcards (*)
+        search_values = [s.strip() for s in search.split(",") if s.strip()]
+        if len(search_values) == 1:
+            search_val = search_values[0]
+            if "*" in search_val:
+                query = query.filter(Tag.name.ilike(search_val.replace("*", "%")))
+            else:
+                query = query.filter(Tag.name.ilike(f"%{search_val}%"))
+        else:
+            search_conditions = []
+            for search_val in search_values:
+                if "*" in search_val:
+                    search_conditions.append(
+                        Tag.name.ilike(search_val.replace("*", "%"))
+                    )
+                else:
+                    search_conditions.append(Tag.name.ilike(f"%{search_val}%"))
+            query = query.filter(or_(*search_conditions))
     if from_date:
         query = query.filter(Tag.created_at >= from_date)
     if to_date:
@@ -4011,7 +4053,10 @@ def list_all_uploads(
         None, description="Filter by deduplication status"
     ),
     search: Optional[str] = Query(None, description="Search by original filename"),
-    tag: Optional[str] = Query(None, description="Filter by tag name"),
+    tag: Optional[str] = Query(
+        None,
+        description="Filter by tag name. Supports wildcards (*) and comma-separated values",
+    ),
     sort: Optional[str] = Query(
         None, description="Sort field: uploaded_at, original_name, size"
     ),
@@ -4055,7 +4100,24 @@ def list_all_uploads(
     if search:
         query = query.filter(Upload.original_name.ilike(f"%{search}%"))
     if tag:
-        query = query.filter(Upload.tag_name == tag)
+        # Support multiple values (comma-separated) and wildcards (*)
+        tag_values = [t.strip() for t in tag.split(",") if t.strip()]
+        if len(tag_values) == 1:
+            tag_val = tag_values[0]
+            if "*" in tag_val:
+                query = query.filter(Upload.tag_name.ilike(tag_val.replace("*", "%")))
+            else:
+                query = query.filter(Upload.tag_name == tag_val)
+        else:
+            tag_conditions = []
+            for tag_val in tag_values:
+                if "*" in tag_val:
+                    tag_conditions.append(
+                        Upload.tag_name.ilike(tag_val.replace("*", "%"))
+                    )
+                else:
+                    tag_conditions.append(Upload.tag_name == tag_val)
+            query = query.filter(or_(*tag_conditions))
 
     # Validate and apply sorting
     valid_sort_fields = {