Add Pathfinder 2e game system mode

Implements PF2e as an alternative game system alongside D&D 5e/5.5e.
Settings modal "Game System" selector switches conditions, bestiary,
stat block layout, and initiative calculation between systems.

- Valued conditions with increment/decrement UX (Clumsy 2, Frightened 3)
- 2,502 PF2e creatures from bundled search index (77 sources)
- PF2e stat block: level, traits, Perception, Fort/Ref/Will, ability mods
- Perception-based initiative rolling
- System-scoped source cache (D&D and PF2e sources don't collide)
- Backwards-compatible condition rehydration (ConditionId[] → ConditionEntry[])
- Difficulty indicator hidden in PF2e mode (excluded from MVP)

Closes dostulata/initiative#19

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

apps/web/src/adapters/__tests__/pf2e-bestiary-index-adapter.test.ts

@@ -0,0 +1,68 @@
+import { describe, expect, it } from "vitest";
+import {
+	getAllPf2eSourceCodes,
+	getDefaultPf2eFetchUrl,
+	getPf2eSourceDisplayName,
+	loadPf2eBestiaryIndex,
+} from "../pf2e-bestiary-index-adapter.js";
+
+describe("loadPf2eBestiaryIndex", () => {
+	it("returns an object with sources and creatures", () => {
+		const index = loadPf2eBestiaryIndex();
+		expect(index.sources).toBeDefined();
+		expect(index.creatures).toBeDefined();
+		expect(Array.isArray(index.creatures)).toBe(true);
+	});
+
+	it("creatures have the expected PF2e shape", () => {
+		const index = loadPf2eBestiaryIndex();
+		expect(index.creatures.length).toBeGreaterThan(0);
+		const first = index.creatures[0];
+		expect(first).toHaveProperty("name");
+		expect(first).toHaveProperty("source");
+		expect(first).toHaveProperty("level");
+		expect(first).toHaveProperty("ac");
+		expect(first).toHaveProperty("hp");
+		expect(first).toHaveProperty("perception");
+		expect(first).toHaveProperty("size");
+		expect(first).toHaveProperty("type");
+	});
+
+	it("contains a substantial number of creatures", () => {
+		const index = loadPf2eBestiaryIndex();
+		expect(index.creatures.length).toBeGreaterThan(2000);
+	});
+
+	it("returns the same cached instance on subsequent calls", () => {
+		const a = loadPf2eBestiaryIndex();
+		const b = loadPf2eBestiaryIndex();
+		expect(a).toBe(b);
+	});
+});
+
+describe("getAllPf2eSourceCodes", () => {
+	it("returns all keys from the index sources", () => {
+		const codes = getAllPf2eSourceCodes();
+		const index = loadPf2eBestiaryIndex();
+		expect(codes).toEqual(Object.keys(index.sources));
+	});
+});
+
+describe("getDefaultPf2eFetchUrl", () => {
+	it("returns Pf2eTools GitHub URL with lowercase source code", () => {
+		const url = getDefaultPf2eFetchUrl("B1");
+		expect(url).toBe(
+			"https://raw.githubusercontent.com/Pf2eToolsOrg/Pf2eTools/dev/data/bestiary/creatures-b1.json",
+		);
+	});
+});
+
+describe("getPf2eSourceDisplayName", () => {
+	it("returns display name for a known source", () => {
+		expect(getPf2eSourceDisplayName("B1")).toBe("Bestiary");
+	});
+
+	it("falls back to source code for unknown source", () => {
+		expect(getPf2eSourceDisplayName("UNKNOWN")).toBe("UNKNOWN");
+	});
+});