Constant MIGRATION_007 

const MIGRATION_007: &str = r#"
-- Recreate thumbnails table without foreign key constraint on item_id
-- and add LRU eviction support columns
CREATE TABLE IF NOT EXISTS thumbnails_new (
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    item_id TEXT NOT NULL,  -- No foreign key constraint - item may not be synced yet
    image_type TEXT NOT NULL,  -- Primary, Backdrop, Thumb, Logo, etc.
    image_tag TEXT NOT NULL,
    file_path TEXT NOT NULL,
    width INTEGER,
    height INTEGER,
    file_size INTEGER DEFAULT 0,  -- Size in bytes for cache limit tracking
    cached_at TEXT DEFAULT CURRENT_TIMESTAMP,
    last_accessed TEXT DEFAULT CURRENT_TIMESTAMP,  -- For LRU eviction
    UNIQUE(item_id, image_type, image_tag)
);

-- Copy existing data (if any)
INSERT OR IGNORE INTO thumbnails_new (id, item_id, image_type, image_tag, file_path, width, height, cached_at)
SELECT id, item_id, image_type, image_tag, file_path, width, height, cached_at FROM thumbnails;

-- Drop old table and rename new one
DROP TABLE IF EXISTS thumbnails;
ALTER TABLE thumbnails_new RENAME TO thumbnails;

-- Create indexes for efficient queries
CREATE INDEX IF NOT EXISTS idx_thumbnails_item ON thumbnails(item_id);
CREATE INDEX IF NOT EXISTS idx_thumbnails_lru ON thumbnails(last_accessed ASC);

-- Cache settings table for configurable limits
CREATE TABLE IF NOT EXISTS cache_settings (
    key TEXT PRIMARY KEY,
    value TEXT NOT NULL,
    updated_at TEXT DEFAULT CURRENT_TIMESTAMP
);

-- Insert default settings
INSERT OR IGNORE INTO cache_settings (key, value) VALUES ('image_cache_limit_bytes', '1073741824');  -- 1GB default
INSERT OR IGNORE INTO cache_settings (key, value) VALUES ('image_cache_enabled', 'true');
"#;

Migration to enhance thumbnail caching with LRU eviction support

• Relaxes foreign key constraint on item_id (allows caching for items not yet synced)
• Adds last_accessed for LRU eviction
• Adds file_size for cache limit tracking
• Creates cache_settings table for configurable limits