Implement the 021-bestiary-statblock feature that adds a searchable D&D 2024 Monster Manual creature library with inline autocomplete suggestions, full stat block display in a fixed side panel, auto-numbering of duplicate creature names, HP/AC pre-fill from bestiary data, and automatic stat block display on turn change for wide viewports

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/domain/src/auto-number.ts

@@ -0,0 +1,54 @@
+/**
+ * Resolves a creature name against existing combatant names,
+ * handling auto-numbering for duplicates.
+ *
+ * - No conflict: returns name as-is, no renames.
+ * - First conflict (one existing match): renames existing to "Name 1",
+ *   new becomes "Name 2".
+ * - Subsequent conflicts: new gets next number suffix.
+ */
+export function resolveCreatureName(
+	baseName: string,
+	existingNames: readonly string[],
+): {
+	newName: string;
+	renames: ReadonlyArray<{ from: string; to: string }>;
+} {
+	// Find exact matches and numbered matches (e.g., "Goblin 1", "Goblin 2")
+	const exactMatches: number[] = [];
+	let maxNumber = 0;
+
+	for (let i = 0; i < existingNames.length; i++) {
+		const name = existingNames[i];
+		if (name === baseName) {
+			exactMatches.push(i);
+		} else {
+			const match = new RegExp(`^${escapeRegExp(baseName)} (\\d+)$`).exec(name);
+			if (match) {
+				const num = Number.parseInt(match[1], 10);
+				if (num > maxNumber) maxNumber = num;
+			}
+		}
+	}
+
+	// No conflict at all
+	if (exactMatches.length === 0 && maxNumber === 0) {
+		return { newName: baseName, renames: [] };
+	}
+
+	// First conflict: one exact match, no numbered ones yet
+	if (exactMatches.length === 1 && maxNumber === 0) {
+		return {
+			newName: `${baseName} 2`,
+			renames: [{ from: baseName, to: `${baseName} 1` }],
+		};
+	}
+
+	// Subsequent conflicts: append next number
+	const nextNumber = Math.max(maxNumber, exactMatches.length) + 1;
+	return { newName: `${baseName} ${nextNumber}`, renames: [] };
+}
+
+function escapeRegExp(s: string): string {
+	return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
+}