Would resilient armor Rune stack with Dragon Disciples Dragon Scale AC bonus?
Resilient runes affect Saves, not AC, so it would stack.
As for Potency, the feat already specifies the items that it would stack with; incidentally, if you had an actual Armor equipped, the Scales wouldn't do anything.
Scales grow across your body, protecting you against physical and magical threats. When you're unarmored, the scales give you a +2 item bonus to AC with a Dexterity cap of +3. The item bonus to AC from Scales of the Dragon is cumulative with armor potency runes on your explorer's clothing, mage armor, and bracers of armor. Your resistance from Dragon Disciple Dedication increases to 3 + half your level.
Resilient runes affect AC, not Saves, so it would stack.Other way around.
Oops. Edited to avoid the confusion.
Would resilient armor Rune stack with Dragon Disciples Dragon Scale AC bonus?
Probably you are talking about the Armor Potency rune.
It's easily to know if the things stacks in PF2. Different bonus types stacks, same not! Simple that.
So Armor Potency runes improves your armor Item bonus (armor potency runes don't give bonus by itself instead it improves the armor item where they are put in. The armor itself is that give the Item bonus) and Scales of the Dragon also gives an Item bonus. It's same type of bonus so they don't stack instead you use the greater.
Same for Status bonuses. If you have 2 sources of Status bonus for a thing (like AC) only the greater is valid.
Also for Circunstance bonuses. When you have 2 sources of Status bonus for a thing only the greater is valid.
The rest with exception of temp HP and resistances/weakness, stacks. Example, additional/extra damage, hardness and other things that aren't classified as item/status/circunstance types stacks normally but are bit rare to merge.
Wow this is a helluva feat then for a squishee Cloistered Cleric.
So Armor Potency runes improves your armor Item bonus (armor potency runes don't give bonus by itself instead it improves the armor item where they are put in. The armor itself is that give the Item bonus) and Scales of the Dragon also gives an Item bonus. It's same type of bonus so they don't stack instead you use the greater.
The feat expressly says that item bonuses to AC via potency runes on Explorer's Clothing, Mage Armor, and Bracers of Armor stack with the item bonus to AC provided by the feat.