feat: Implement file upload and management system with database integration

src/lib/init-db.js

@@ -341,4 +341,26 @@ export default function initializeDatabase() {
 	} catch (e) {
 		console.warn("Migration warning:", e.message);
 	}
+
+	// Generic file attachments table
+	db.exec(`
+		CREATE TABLE IF NOT EXISTS file_attachments (
+			file_id INTEGER PRIMARY KEY AUTOINCREMENT,
+			entity_type TEXT NOT NULL CHECK(entity_type IN ('contract', 'project', 'task')),
+			entity_id INTEGER NOT NULL,
+			original_filename TEXT NOT NULL,
+			stored_filename TEXT NOT NULL,
+			file_path TEXT NOT NULL,
+			file_size INTEGER,
+			mime_type TEXT,
+			description TEXT,
+			uploaded_by TEXT,
+			upload_date TEXT DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (uploaded_by) REFERENCES users(id)
+		);
+
+		-- Create indexes for file attachments
+		CREATE INDEX IF NOT EXISTS idx_file_attachments_entity ON file_attachments(entity_type, entity_id);
+		CREATE INDEX IF NOT EXISTS idx_file_attachments_uploaded_by ON file_attachments(uploaded_by);
+	`);
 }