Add inline migration for tag removal (024_remove_tags)

Adds the tag removal migration to the inline migrations in database.py:
- Drops tag-related triggers and functions
- Removes tag_constraint column from artifact_dependencies
- Makes version_constraint NOT NULL
- Drops tags and tag_history tables
- Renames uploads.tag_name to version

backend/app/database.py

@@ -538,6 +538,62 @@ def _run_migrations():
             WHERE name IN ('npm-public', 'pypi-public', 'maven-central', 'docker-hub');
             """,
         ),
+        Migration(
+            name="024_remove_tags",
+            sql="""
+            -- Remove tag system, keeping only versions for artifact references
+            DO $$
+            BEGIN
+                -- Drop triggers on tags table (if they exist)
+                DROP TRIGGER IF EXISTS tags_ref_count_insert_trigger ON tags;
+                DROP TRIGGER IF EXISTS tags_ref_count_delete_trigger ON tags;
+                DROP TRIGGER IF EXISTS tags_ref_count_update_trigger ON tags;
+                DROP TRIGGER IF EXISTS tags_updated_at_trigger ON tags;
+                DROP TRIGGER IF EXISTS tag_changes_trigger ON tags;
+
+                -- Drop the tag change tracking function
+                DROP FUNCTION IF EXISTS track_tag_changes();
+
+                -- Remove tag_constraint from artifact_dependencies
+                IF EXISTS (
+                    SELECT 1 FROM information_schema.table_constraints
+                    WHERE constraint_name = 'check_constraint_type'
+                    AND table_name = 'artifact_dependencies'
+                ) THEN
+                    ALTER TABLE artifact_dependencies DROP CONSTRAINT check_constraint_type;
+                END IF;
+
+                -- Remove the tag_constraint column if it exists
+                IF EXISTS (
+                    SELECT 1 FROM information_schema.columns
+                    WHERE table_name = 'artifact_dependencies' AND column_name = 'tag_constraint'
+                ) THEN
+                    ALTER TABLE artifact_dependencies DROP COLUMN tag_constraint;
+                END IF;
+
+                -- Make version_constraint NOT NULL
+                UPDATE artifact_dependencies SET version_constraint = '*' WHERE version_constraint IS NULL;
+                ALTER TABLE artifact_dependencies ALTER COLUMN version_constraint SET NOT NULL;
+
+                -- Drop tag_history table first (depends on tags)
+                DROP TABLE IF EXISTS tag_history;
+
+                -- Drop tags table
+                DROP TABLE IF EXISTS tags;
+
+                -- Rename uploads.tag_name to version if it exists and version doesn't
+                IF EXISTS (
+                    SELECT 1 FROM information_schema.columns
+                    WHERE table_name = 'uploads' AND column_name = 'tag_name'
+                ) AND NOT EXISTS (
+                    SELECT 1 FROM information_schema.columns
+                    WHERE table_name = 'uploads' AND column_name = 'version'
+                ) THEN
+                    ALTER TABLE uploads RENAME COLUMN tag_name TO version;
+                END IF;
+            END $$;
+            """,
+        ),
     ]
 
     with engine.connect() as conn: