Remove tag system, use versions only for artifact references

Tags were mutable aliases that caused confusion alongside the immutable
version system. This removes tags entirely, keeping only PackageVersion
for artifact references.

Changes:
- Remove tags and tag_history tables (migration 012)
- Remove Tag model, TagRepository, and 6 tag API endpoints
- Update cache system to create versions instead of tags
- Update frontend to display versions instead of tags
- Remove tag-related schemas and types
- Update artifact cleanup service for version-based ref_count

backend/app/purge_seed_data.py

@@ -12,7 +12,6 @@ from .models import (
     Project,
     Package,
     Artifact,
-    Tag,
     Upload,
     PackageVersion,
     ArtifactDependency,
@@ -60,7 +59,6 @@ def purge_seed_data(db: Session) -> dict:
 
     results = {
         "dependencies_deleted": 0,
-        "tags_deleted": 0,
         "versions_deleted": 0,
         "uploads_deleted": 0,
         "artifacts_deleted": 0,
@@ -103,15 +101,7 @@ def purge_seed_data(db: Session) -> dict:
         results["dependencies_deleted"] = count
         logger.info(f"Deleted {count} artifact dependencies")
 
-    # 2. Delete tags
-    if seed_package_ids:
-        count = db.query(Tag).filter(Tag.package_id.in_(seed_package_ids)).delete(
-            synchronize_session=False
-        )
-        results["tags_deleted"] = count
-        logger.info(f"Deleted {count} tags")
-
-    # 3. Delete package versions
+    # 2. Delete package versions
     if seed_package_ids:
         count = db.query(PackageVersion).filter(
             PackageVersion.package_id.in_(seed_package_ids)
@@ -119,7 +109,7 @@ def purge_seed_data(db: Session) -> dict:
         results["versions_deleted"] = count
         logger.info(f"Deleted {count} package versions")
 
-    # 4. Delete uploads
+    # 3. Delete uploads
     if seed_package_ids:
         count = db.query(Upload).filter(Upload.package_id.in_(seed_package_ids)).delete(
             synchronize_session=False
@@ -127,7 +117,7 @@ def purge_seed_data(db: Session) -> dict:
         results["uploads_deleted"] = count
         logger.info(f"Deleted {count} uploads")
 
-    # 5. Delete S3 objects for seed artifacts
+    # 4. Delete S3 objects for seed artifacts
     if seed_artifact_ids:
         seed_artifacts = db.query(Artifact).filter(Artifact.id.in_(seed_artifact_ids)).all()
         for artifact in seed_artifacts:
@@ -139,8 +129,8 @@ def purge_seed_data(db: Session) -> dict:
                     logger.warning(f"Failed to delete S3 object {artifact.s3_key}: {e}")
         logger.info(f"Deleted {results['s3_objects_deleted']} S3 objects")
 
-    # 6. Delete artifacts (only those with ref_count that would be 0 after our deletions)
-    # Since we deleted all tags/versions pointing to these artifacts, we can delete them
+    # 5. Delete artifacts (only those with ref_count that would be 0 after our deletions)
+    # Since we deleted all versions pointing to these artifacts, we can delete them
     if seed_artifact_ids:
         count = db.query(Artifact).filter(Artifact.id.in_(seed_artifact_ids)).delete(
             synchronize_session=False
@@ -148,7 +138,7 @@ def purge_seed_data(db: Session) -> dict:
         results["artifacts_deleted"] = count
         logger.info(f"Deleted {count} artifacts")
 
-    # 7. Delete packages
+    # 6. Delete packages
     if seed_package_ids:
         count = db.query(Package).filter(Package.id.in_(seed_package_ids)).delete(
             synchronize_session=False
@@ -156,7 +146,7 @@ def purge_seed_data(db: Session) -> dict:
         results["packages_deleted"] = count
         logger.info(f"Deleted {count} packages")
 
-    # 8. Delete access permissions for seed projects
+    # 7. Delete access permissions for seed projects
     if seed_project_ids:
         count = db.query(AccessPermission).filter(
             AccessPermission.project_id.in_(seed_project_ids)
@@ -164,14 +154,14 @@ def purge_seed_data(db: Session) -> dict:
         results["permissions_deleted"] = count
         logger.info(f"Deleted {count} access permissions")
 
-    # 9. Delete seed projects
+    # 8. Delete seed projects
     count = db.query(Project).filter(Project.name.in_(SEED_PROJECT_NAMES)).delete(
         synchronize_session=False
     )
     results["projects_deleted"] = count
     logger.info(f"Deleted {count} projects")
 
-    # 10. Find and delete seed team
+    # 9. Find and delete seed team
     seed_team = db.query(Team).filter(Team.slug == SEED_TEAM_SLUG).first()
     if seed_team:
         # Delete team memberships first
@@ -186,7 +176,7 @@ def purge_seed_data(db: Session) -> dict:
         results["teams_deleted"] = 1
         logger.info(f"Deleted team: {SEED_TEAM_SLUG}")
 
-    # 11. Delete seed users (but NOT admin)
+    # 10. Delete seed users (but NOT admin)
     seed_users = db.query(User).filter(User.username.in_(SEED_USERNAMES)).all()
     for user in seed_users:
         # Delete any remaining team memberships for this user