Rewrite Foulborn generation with proper mod replacement logic

Instead of appending mutation mods as variants to the original's base
mods, the new logic properly replaces specific original mods with their
Foulborn mutations -- matching the actual in-game behavior.

Key changes:
- Add ModFoulbornPairs.lua: mutation slot pairing table (239 uniques)
  extracted from PR #9432's static item data, defining which original
  mods get removed and what replaces them per mutation slot
- Rewrite Generated.lua Foulborn block: for each unique, enumerate all
  non-empty subsets of mutation slots (2^n - 1 items per unique), remove
  matched mods and add mutated replacements with "(mutated)" suffix
- Add warning system: ConPrintf flags uniques in ModFoulbornMap that
  lack pairing data in ModFoulbornPairs (22 uniques currently)
- Update tests: 14 tests covering item count (437), per-unique counts,
  mod replacement verification, implicit handling, Skin of the Lords
- Remove dumpModEquivalencies.lua (no longer needed)

Total: 437 generated Foulborn items with correct replacement semantics.

Author: EtherealCarnivore

spec/System/TestFoulborn_spec.lua

@@ -1,56 +1,106 @@
 describe("Foulborn generation", function()
-	it("generates Foulborn items from foulbornMap", function()
+	it("generates correct number of Foulborn items", function()
 		local foulbornCount = 0
 		for _, raw in ipairs(data.uniques.generated) do
 			if raw:match("^Foulborn ") then
 				foulbornCount = foulbornCount + 1
 			end
 		end
-		assert.is_true(foulbornCount > 200, "Expected 200+ Foulborn items, got " .. foulbornCount)
+		-- PR #9432 has 440 items total; Skin of the Lords is tree-dependent (separate function)
+		-- so we expect ~439 non-tree-dependent items
+		assert.is_true(foulbornCount >= 430, "Expected 430+ Foulborn items, got " .. foulbornCount)
 		print("  Foulborn items generated: " .. foulbornCount)
 	end)
 
-	it("generates valid Foulborn Alpha's Howl", function()
+	it("generates correct number of Headhunter items (2^3-1=7)", function()
+		local count = 0
+		for _, raw in ipairs(data.uniques.generated) do
+			if raw:match("^Foulborn Headhunter %d+\n") then
+				count = count + 1
+			end
+		end
+		assert.are.equals(7, count, "Headhunter should have 7 Foulborn items (3 slots)")
+	end)
+
+	it("generates correct number of Alpha's Howl items (2^2-1=3)", function()
+		local count = 0
+		for _, raw in ipairs(data.uniques.generated) do
+			if raw:match("^Foulborn Alpha's Howl %d+\n") then
+				count = count + 1
+			end
+		end
+		assert.are.equals(3, count, "Alpha's Howl should have 3 Foulborn items (2 slots)")
+	end)
+
+	it("verifies mod replacement in Headhunter 1", function()
 		local raw
 		for _, r in ipairs(data.uniques.generated) do
-			if r:match("^Foulborn Alpha") then raw = r; break end
+			if r:match("^Foulborn Headhunter 1\n") then raw = r; break end
 		end
-		assert.is_truthy(raw, "Foulborn Alpha's Howl not found")
+		assert.is_truthy(raw, "Foulborn Headhunter 1 not found")
+		-- Should have Culling Strike (mutated) as the added mod
+		assert.truthy(raw:match("Culling Strike %(mutated%)"), "Missing added mod 'Culling Strike (mutated)'")
+		-- Should NOT have the removed mod
+		assert.is_falsy(raw:match("increased Damage with Hits against Rare monsters"), "Removed mod should not be present")
+		-- Should still have other original mods
+		assert.truthy(raw:match("When you Kill a Rare monster"), "Missing original mod that should be preserved")
+		assert.truthy(raw:match("Leather Belt"), "Missing base type")
+	end)
+
+	it("verifies Headhunter 7 has all three mutations", function()
+		local raw
+		for _, r in ipairs(data.uniques.generated) do
+			if r:match("^Foulborn Headhunter 7\n") then raw = r; break end
+		end
+		assert.is_truthy(raw, "Foulborn Headhunter 7 not found")
+		assert.truthy(raw:match("Culling Strike %(mutated%)"), "Missing Culling Strike")
+		assert.truthy(raw:match("Eat a Soul.-%(mutated%)"), "Missing Eat a Soul")
+		assert.truthy(raw:match("Minimap Icons.-%(mutated%)"), "Missing Minimap Icons")
+		-- All three original mods should be removed
+		assert.is_falsy(raw:match("increased Damage with Hits against Rare monsters"), "Removed mod still present")
+		assert.is_falsy(raw:match("When you Kill a Rare monster, you gain its Modifiers"), "Removed mod still present")
+	end)
+
+	it("generates valid Foulborn Alpha's Howl 1", function()
+		local raw
+		for _, r in ipairs(data.uniques.generated) do
+			if r:match("^Foulborn Alpha's Howl 1\n") then raw = r; break end
+		end
+		assert.is_truthy(raw, "Foulborn Alpha's Howl 1 not found")
 		assert.truthy(raw:match("Sinner Tricorne"), "Missing base type")
-		assert.truthy(raw:match("Variant:"), "Missing variant declarations")
-		assert.truthy(raw:match("{variant:1}"), "Missing variant-tagged mod")
 		assert.truthy(raw:match("Requires Level"), "Missing requires line")
+		-- Should have added mod and NOT have removed mod
+		assert.truthy(raw:match("Life Reservation Efficiency.-%(mutated%)"), "Missing added mutation mod")
+		assert.is_falsy(raw:match("16%% increased Mana Reservation Efficiency"), "Removed mod should not be present")
 	end)
 
 	it("parses Foulborn item with foulborn flag", function()
 		newBuild()
 		local raw
 		for _, r in ipairs(data.uniques.generated) do
-			if r:match("^Foulborn Alpha") then raw = r; break end
+			if r:match("^Foulborn Alpha's Howl 1\n") then raw = r; break end
 		end
 		local item = new("Item", raw)
 		assert.is_true(item.foulborn, "foulborn flag not set")
 		assert.are.equals("Sinner Tricorne", item.baseName)
-		assert.are.equals("Foulborn Alpha's Howl", item.title)
-		assert.is_true(#item.variantList > 0, "No variants parsed")
-		print("  Variants: " .. #item.variantList)
+		assert.are.equals("Foulborn Alpha's Howl 1", item.title)
 	end)
 
 	it("generates Foulborn item with existing variants correctly", function()
 		local raw
 		for _, r in ipairs(data.uniques.generated) do
-			if r:match("^Foulborn The Formless Flame") then raw = r; break end
+			if r:match("^Foulborn The Formless Flame %d+\n") then raw = r; break end
 		end
 		assert.is_truthy(raw, "Foulborn The Formless Flame not found")
-		-- Should use Current variant base (Royal Burgonet, not Siege Helmet)
-		assert.truthy(raw:match("Royal Burgonet"), "Wrong base type - should be Royal Burgonet (Current variant)")
+		-- Should use current variant base (Royal Burgonet, not Siege Helmet)
+		assert.truthy(raw:match("Royal Burgonet"), "Wrong base type - should be Royal Burgonet (current variant)")
 		assert.is_falsy(raw:match("Siege Helmet"), "Should not contain old variant base")
 	end)
 
 	it("generates Foulborn item with implicits", function()
 		local raw
 		for _, r in ipairs(data.uniques.generated) do
-			if r:match("^Foulborn Call of the Brotherhood") then raw = r; break end
+			if r:match("^Foulborn Call of the Brotherhood %d+\n") then raw = r; break end
 		end
 		assert.is_truthy(raw, "Foulborn Call of the Brotherhood not found")
 		assert.truthy(raw:match("Implicits: 1"), "Missing implicits declaration")
@@ -61,7 +111,7 @@ describe("Foulborn generation", function()
 		newBuild()
 		local raw
 		for _, r in ipairs(data.uniques.generated) do
-			if r:match("^Foulborn Call of the Brotherhood") then raw = r; break end
+			if r:match("^Foulborn Call of the Brotherhood %d+\n") then raw = r; break end
 		end
 		assert.is_truthy(raw, "Foulborn Call of the Brotherhood not found")
 		local item = new("Item", raw)
@@ -117,4 +167,18 @@ describe("Foulborn generation", function()
 		assert.is_true(#item.variantList > 30, "Not enough variants parsed")
 		print("  Parsed variants: " .. #item.variantList .. ", hasAltVariant: " .. tostring(item.hasAltVariant))
 	end)
+
+	it("generates items with (mutated) tag on all added mods", function()
+		local issues = {}
+		for _, raw in ipairs(data.uniques.generated) do
+			if raw:match("^Foulborn ") and not raw:match("^Foulborn Skin of the Lords") then
+				local hasMutated = raw:match("%(mutated%)")
+				if not hasMutated then
+					local name = raw:match("^(.-)\n")
+					table.insert(issues, name)
+				end
+			end
+		end
+		assert.are.equals(0, #issues, "Items without (mutated) tag: " .. table.concat(issues, ", "))
+	end)
 end)