Harden radius jewel comparison follow-up

Strengthen the replacement tooltip test, preserve traceback when rebuilding comparison specs, and document the PassiveSpec field allowlist.

Addresses full-branch review follow-ups from exploration 20260512T124426Z-codex-exploration-159337fbb665 and request 20260512T125918Z-codex-1dca732498d9.

Author: mcagnion

spec/System/TestRadiusJewelStatDiff_spec.lua

@@ -461,6 +461,8 @@ describe("TestRadiusJewelStatDiff", function()
 
 		assert.is_true(tooltipContains(tooltip, "Equipping this item in"),
 			"Replacing the radius jewel should show the stat loss from unsupported nodes")
+		assert.is_true(tooltipContainsNegativeStat(tooltip, "Total Life"),
+			"Replacing the radius jewel should remove the life node only supported by that jewel:\n" .. tooltipText(tooltip))
 	end)
 
 	it("intuitiveLeapLike removal comparison keeps nodes supported by another radius jewel", function()

src/Classes/ItemsTab.lua

@@ -3504,6 +3504,8 @@ end
 
 -- Radius jewels can change conquered nodes and orphaned allocations, so compare
 -- against a rebuilt spec instead of approximating the diff with removeNodes.
+-- Keep this list in sync with PassiveSpec's constructor, Init, and Select*
+-- methods; omitted fields fail safe as nil on the comparison spec.
 local sharedSpecKeysForJewelComparison = {
 	build = true,
 	treeVersion = true,
@@ -3594,9 +3596,9 @@ local function buildSpecForJewelComparison(itemsTab, compareSlot, replacementIte
 		spec.jewels[compareSlot.nodeId] = nil
 	end
 
-	local ok, err = pcall(function()
+	local ok, err = xpcall(function()
 		spec:BuildAllDependsAndPaths()
-	end)
+	end, debug.traceback)
 	if tempItemId then
 		itemsTab.items[tempItemId] = nil
 	end