Add 2014 DMG encounter difficulty calculation

Support the 2014 DMG encounter difficulty as an alternative to the 5.5e
system behind the existing Rules Edition toggle. The 2014 system uses
Easy/Medium/Hard/Deadly thresholds, an encounter multiplier based on
monster count, and party size adjustment (×0.5–×5 range).

- Extract RulesEdition to its own domain module
- Refactor DifficultyTier to abstract numeric values (0–3)
- Restructure DifficultyResult with thresholds array
- Add 2014 XP thresholds table and encounter multiplier logic
- Wire edition from context into difficulty hooks
- Edition-aware labels in indicator and breakdown panel
- Show multiplier, adjusted XP, and party size note for 2014
- Rename settings label from "Conditions" to "Rules Edition"
- Update spec 008 with issue #23 requirements

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/components/__tests__/difficulty-breakdown-panel.test.tsx

@@ -3,7 +3,13 @@ import "@testing-library/jest-dom/vitest";
 
 import type { Creature, CreatureId, PlayerCharacter } from "@initiative/domain";
 import { combatantId, creatureId, playerCharacterId } from "@initiative/domain";
-import { cleanup, render, screen, waitFor } from "@testing-library/react";
+import {
+	cleanup,
+	render,
+	renderHook,
+	screen,
+	waitFor,
+} from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { afterEach, beforeAll, describe, expect, it, vi } from "vitest";
 import { createTestAdapters } from "../../__tests__/adapters/in-memory-adapters.js";
@@ -13,6 +19,7 @@ import {
 	buildEncounter,
 } from "../../__tests__/factories/index.js";
 import { AllProviders } from "../../__tests__/test-providers.js";
+import { useRulesEdition } from "../../hooks/use-rules-edition.js";
 import { DifficultyBreakdownPanel } from "../difficulty-breakdown-panel.js";
 
 beforeAll(() => {
@@ -279,6 +286,63 @@ describe("DifficultyBreakdownPanel", () => {
 		expect(container.innerHTML).toBe("");
 	});
 
+	it("shows 4 threshold columns for 2014 edition", async () => {
+		const { result: editionResult } = renderHook(() => useRulesEdition());
+		editionResult.current.setEdition("5e");
+
+		try {
+			renderPanel({
+				encounter: defaultEncounter(),
+				playerCharacters: defaultPCs,
+				creatures: new Map([[goblinCreature.id, goblinCreature]]),
+			});
+
+			await waitFor(() => {
+				expect(screen.getByText("Easy:", { exact: false })).toBeInTheDocument();
+				expect(screen.getByText("Med:", { exact: false })).toBeInTheDocument();
+				expect(screen.getByText("Hard:", { exact: false })).toBeInTheDocument();
+				expect(
+					screen.getByText("Deadly:", { exact: false }),
+				).toBeInTheDocument();
+			});
+		} finally {
+			editionResult.current.setEdition("5.5e");
+		}
+	});
+
+	it("shows multiplier and adjusted XP for 2014 edition", async () => {
+		const { result: editionResult } = renderHook(() => useRulesEdition());
+		editionResult.current.setEdition("5e");
+
+		try {
+			renderPanel({
+				encounter: defaultEncounter(),
+				playerCharacters: defaultPCs,
+				creatures: new Map([[goblinCreature.id, goblinCreature]]),
+			});
+
+			await waitFor(() => {
+				expect(screen.getByText("Monster XP")).toBeInTheDocument();
+				// 1 PC (<3) triggers party size adjustment
+				expect(screen.getByText("Adjusted for 1 PC")).toBeInTheDocument();
+			});
+		} finally {
+			editionResult.current.setEdition("5.5e");
+		}
+	});
+
+	it("shows Net Monster XP for 5.5e edition (no multiplier)", async () => {
+		renderPanel({
+			encounter: defaultEncounter(),
+			playerCharacters: defaultPCs,
+			creatures: new Map([[goblinCreature.id, goblinCreature]]),
+		});
+
+		await waitFor(() => {
+			expect(screen.getByText("Net Monster XP")).toBeInTheDocument();
+		});
+	});
+
 	it("calls onClose when Escape is pressed", async () => {
 		const user = userEvent.setup();
 		const onClose = vi.fn();

apps/web/src/components/__tests__/difficulty-indicator.test.tsx

@@ -3,7 +3,11 @@ import type { DifficultyResult } from "@initiative/domain";
 import { cleanup, render, screen } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { afterEach, describe, expect, it, vi } from "vitest";
-import { DifficultyIndicator } from "../difficulty-indicator.js";
+import {
+	DifficultyIndicator,
+	TIER_LABELS_5_5E,
+	TIER_LABELS_2014,
+} from "../difficulty-indicator.js";
 
 afterEach(cleanup);
 
@@ -11,50 +15,77 @@ function makeResult(tier: DifficultyResult["tier"]): DifficultyResult {
 	return {
 		tier,
 		totalMonsterXp: 100,
-		partyBudget: { low: 50, moderate: 100, high: 200 },
+		thresholds: [
+			{ label: "Low", value: 50 },
+			{ label: "Moderate", value: 100 },
+			{ label: "High", value: 200 },
+		],
+		encounterMultiplier: undefined,
+		adjustedXp: undefined,
+		partySizeAdjusted: undefined,
 	};
 }
 
 describe("DifficultyIndicator", () => {
 	it("renders 3 bars", () => {
 		const { container } = render(
-			<DifficultyIndicator result={makeResult("moderate")} />,
+			<DifficultyIndicator result={makeResult(2)} labels={TIER_LABELS_5_5E} />,
 		);
 		const bars = container.querySelectorAll("[class*='rounded-sm']");
 		expect(bars).toHaveLength(3);
 	});
 
-	it("shows 'Trivial encounter difficulty' label for trivial tier", () => {
-		render(<DifficultyIndicator result={makeResult("trivial")} />);
+	it("shows 'Trivial encounter difficulty' for 5.5e tier 0", () => {
+		render(
+			<DifficultyIndicator result={makeResult(0)} labels={TIER_LABELS_5_5E} />,
+		);
 		expect(
-			screen.getByRole("img", {
-				name: "Trivial encounter difficulty",
-			}),
+			screen.getByRole("img", { name: "Trivial encounter difficulty" }),
 		).toBeDefined();
 	});
 
-	it("shows 'Low encounter difficulty' label for low tier", () => {
-		render(<DifficultyIndicator result={makeResult("low")} />);
+	it("shows 'Low encounter difficulty' for 5.5e tier 1", () => {
+		render(
+			<DifficultyIndicator result={makeResult(1)} labels={TIER_LABELS_5_5E} />,
+		);
 		expect(
 			screen.getByRole("img", { name: "Low encounter difficulty" }),
 		).toBeDefined();
 	});
 
-	it("shows 'Moderate encounter difficulty' label for moderate tier", () => {
-		render(<DifficultyIndicator result={makeResult("moderate")} />);
+	it("shows 'Moderate encounter difficulty' for 5.5e tier 2", () => {
+		render(
+			<DifficultyIndicator result={makeResult(2)} labels={TIER_LABELS_5_5E} />,
+		);
 		expect(
-			screen.getByRole("img", {
-				name: "Moderate encounter difficulty",
-			}),
+			screen.getByRole("img", { name: "Moderate encounter difficulty" }),
 		).toBeDefined();
 	});
 
-	it("shows 'High encounter difficulty' label for high tier", () => {
-		render(<DifficultyIndicator result={makeResult("high")} />);
+	it("shows 'High encounter difficulty' for 5.5e tier 3", () => {
+		render(
+			<DifficultyIndicator result={makeResult(3)} labels={TIER_LABELS_5_5E} />,
+		);
 		expect(
-			screen.getByRole("img", {
-				name: "High encounter difficulty",
-			}),
+			screen.getByRole("img", { name: "High encounter difficulty" }),
+		).toBeDefined();
+	});
+
+	it("shows 'Easy encounter difficulty' for 2014 tier 0", () => {
+		render(
+			<DifficultyIndicator result={makeResult(0)} labels={TIER_LABELS_2014} />,
+		);
+		expect(
+			screen.getByRole("img", { name: "Easy encounter difficulty" }),
+		).toBeDefined();
+	});
+
+	it("shows 'Deadly encounter difficulty' for 2014 tier 3", () => {
+		render(
+			<DifficultyIndicator result={makeResult(3)} labels={TIER_LABELS_2014} />,
+		);
+		expect(
+			screen.getByRole("img", { name: "Deadly encounter difficulty" }),
 		).toBeDefined();
 	});
 
@@ -63,22 +94,21 @@ describe("DifficultyIndicator", () => {
 		const handleClick = vi.fn();
 		render(
 			<DifficultyIndicator
-				result={makeResult("moderate")}
+				result={makeResult(2)}
+				labels={TIER_LABELS_5_5E}
 				onClick={handleClick}
 			/>,
 		);
 
 		await user.click(
-			screen.getByRole("img", {
-				name: "Moderate encounter difficulty",
-			}),
+			screen.getByRole("img", { name: "Moderate encounter difficulty" }),
 		);
 		expect(handleClick).toHaveBeenCalledOnce();
 	});
 
 	it("renders as div when onClick not provided", () => {
 		const { container } = render(
-			<DifficultyIndicator result={makeResult("moderate")} />,
+			<DifficultyIndicator result={makeResult(2)} labels={TIER_LABELS_5_5E} />,
 		);
 		const element = container.querySelector("[role='img']");
 		expect(element?.tagName).toBe("DIV");
@@ -87,7 +117,8 @@ describe("DifficultyIndicator", () => {
 	it("renders as button when onClick provided", () => {
 		const { container } = render(
 			<DifficultyIndicator
-				result={makeResult("moderate")}
+				result={makeResult(2)}
+				labels={TIER_LABELS_5_5E}
 				onClick={() => {}}
 			/>,
 		);

apps/web/src/components/__tests__/settings-modal.test.tsx

@@ -37,8 +37,9 @@ function renderModal(open = true) {
 }
 
 describe("SettingsModal", () => {
-	it("renders edition toggle buttons", () => {
+	it("renders edition section with 'Rules Edition' label", () => {
 		renderModal();
+		expect(screen.getByText("Rules Edition")).toBeInTheDocument();
 		expect(
 			screen.getByRole("button", { name: "5e (2014)" }),
 		).toBeInTheDocument();