feat: poll/voting system with live results and bar charts

backend/db.js

@@ -179,6 +179,27 @@ async function initSchema(connection) {
     created_at DATETIME DEFAULT CURRENT_TIMESTAMP
   ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);
 
+  await createIfNotExists('polls', `CREATE TABLE polls (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    title VARCHAR(200) NOT NULL,
+    description TEXT,
+    options JSON NOT NULL,
+    active TINYINT(1) NOT NULL DEFAULT 1,
+    created_by INT,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    INDEX idx_active (active)
+  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);
+
+  await createIfNotExists('poll_votes', `CREATE TABLE poll_votes (
+    id INT AUTO_INCREMENT PRIMARY KEY,
+    poll_id INT NOT NULL,
+    user_id INT NOT NULL,
+    option_index INT NOT NULL,
+    created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
+    UNIQUE KEY uk_poll_user (poll_id, user_id),
+    INDEX idx_poll (poll_id)
+  ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4`);
+
   await createIfNotExists('audit_logs', `CREATE TABLE audit_logs (
     id INT AUTO_INCREMENT PRIMARY KEY,
     user_id INT,