Add structured talent mechanics

database/schema.sql

@@ -271,6 +271,9 @@ CREATE TABLE IF NOT EXISTS talents (
 	id TEXT PRIMARY KEY,
 	name TEXT NOT NULL,
 	category TEXT NOT NULL CHECK(category IN ('Weapon', 'Backpack', 'Body Armor', 'Vest')),
+	cooldown_seconds REAL CHECK(cooldown_seconds IS NULL OR cooldown_seconds > 0),
+	duration_seconds REAL CHECK(duration_seconds IS NULL OR duration_seconds > 0),
+	max_stacks INTEGER CHECK(max_stacks IS NULL OR max_stacks > 0),
 	active INTEGER NOT NULL DEFAULT 1,
 	created_at TEXT NOT NULL,
 	updated_at TEXT NOT NULL