Whisk the milk, yogurt, date syrup, vanilla, and salt together for 30 seconds until the yogurt is fully dispersed and no pale streaks remain.
While whisking continuously, sprinkle the chia seeds slowly across the surface over about 20 seconds. Continue whisking for another 45 seconds, reaching the bottom and edges of the bowl.
After 5 minutes, whisk again for 30 seconds, pressing any visible clusters against the side of the bowl. Check once more at 15 minutes and stir briefly if the bottom feels denser than the surface.
Divide the mixture among four jars, cover, and refrigerate for at least 4 hours or overnight.
Combine the pears and water in a small saucepan over medium heat. Cook for 5 minutes, stirring twice, then add lemon juice, cardamom, and cinnamon. Cook for another 2–3 minutes until the pear is tender at the edges but still holds its shape. Spread on a plate and cool completely before topping the pudding.
Before serving, stir each jar from bottom to top. If too thick, fold in 1 tablespoon milk at a time. Spoon the cooled pear over each jar and scatter pistachios on top just before eating.