feat(modules): soft delete with restore and active filter

db/migration.sql

@@ -228,8 +228,10 @@ CREATE TABLE IF NOT EXISTS modules (
   id SERIAL PRIMARY KEY,
   name VARCHAR(200) NOT NULL UNIQUE,
   lessons_count INT NOT NULL DEFAULT 0,
+  is_active BOOLEAN NOT NULL DEFAULT true,
   created_at TIMESTAMPTZ DEFAULT now()
 );
 
+ALTER TABLE modules ADD COLUMN IF NOT EXISTS is_active BOOLEAN NOT NULL DEFAULT true;
 ALTER TABLE entries ADD COLUMN IF NOT EXISTS module_id INT REFERENCES modules(id) ON DELETE SET NULL;
 CREATE INDEX IF NOT EXISTS idx_entries_module_id ON entries(module_id);