Add jsinspect-plus structural duplication gate, extract shared helpers

Add jsinspect-plus (AST-based structural duplication detector) to pnpm
check with threshold 50 / min 3 instances. Fix all findings:

- Extract condition icon/color maps to shared condition-styles.ts
- Extract useClickOutside hook (5 components)
- Extract dispatchAction + resolveAndRename in use-encounter
- Extract runEncounterAction in application layer (13 use cases)
- Extract findCombatant helper in domain (9 functions)
- Extract TraitSection in stat-block (4 trait rendering blocks)
- Extract DialogHeader in dialog.tsx (4 dialogs)

Net result: -263 lines across 40 files.

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

packages/domain/src/adjust-hp.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface AdjustHpSuccess {
 	readonly encounter: Encounter;
@@ -17,17 +23,9 @@ export function adjustHp(
 	combatantId: CombatantId,
 	delta: number,
 ): AdjustHpSuccess | DomainError {
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
-
-	const target = encounter.combatants[targetIdx];
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
+	const { combatant: target } = found;
 
 	if (target.maxHp === undefined || target.currentHp === undefined) {
 		return {

packages/domain/src/edit-combatant.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface EditCombatantSuccess {
 	readonly encounter: Encounter;
@@ -30,17 +36,9 @@ export function editCombatant(
 		};
 	}
 
-	const index = encounter.combatants.findIndex((c) => c.id === id);
-
-	if (index === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${id}"`,
-		};
-	}
-
-	const oldName = encounter.combatants[index].name;
+	const found = findCombatant(encounter, id);
+	if (isDomainError(found)) return found;
+	const oldName = found.combatant.name;
 
 	return {
 		encounter: {

packages/domain/src/index.ts

@@ -126,6 +126,7 @@ export {
 	createEncounter,
 	type DomainError,
 	type Encounter,
+	findCombatant,
 	isDomainError,
 } from "./types.js";
 export {

packages/domain/src/remove-combatant.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface RemoveCombatantSuccess {
 	readonly encounter: Encounter;
@@ -22,17 +28,10 @@ export function removeCombatant(
 	encounter: Encounter,
 	id: CombatantId,
 ): RemoveCombatantSuccess | DomainError {
-	const removedIdx = encounter.combatants.findIndex((c) => c.id === id);
+	const found = findCombatant(encounter, id);
+	if (isDomainError(found)) return found;
 
-	if (removedIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${id}"`,
-		};
-	}
-
-	const removed = encounter.combatants[removedIdx];
+	const { index: removedIdx, combatant: removed } = found;
 	const newCombatants = encounter.combatants.filter((_, i) => i !== removedIdx);
 
 	let newActiveIndex: number;

packages/domain/src/set-ac.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface SetAcSuccess {
 	readonly encounter: Encounter;
@@ -11,15 +17,8 @@ export function setAc(
 	combatantId: CombatantId,
 	value: number | undefined,
 ): SetAcSuccess | DomainError {
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
 
 	if (value !== undefined && (!Number.isInteger(value) || value < 0)) {
 		return {
@@ -29,8 +28,7 @@ export function setAc(
 		};
 	}
 
-	const target = encounter.combatants[targetIdx];
-	const previousAc = target.ac;
+	const previousAc = found.combatant.ac;
 
 	const updatedCombatants = encounter.combatants.map((c) =>
 		c.id === combatantId ? { ...c, ac: value } : c,

packages/domain/src/set-hp.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface SetHpSuccess {
 	readonly encounter: Encounter;
@@ -18,15 +24,8 @@ export function setHp(
 	combatantId: CombatantId,
 	maxHp: number | undefined,
 ): SetHpSuccess | DomainError {
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
 
 	if (maxHp !== undefined && (!Number.isInteger(maxHp) || maxHp < 1)) {
 		return {
@@ -36,9 +35,8 @@ export function setHp(
 		};
 	}
 
-	const target = encounter.combatants[targetIdx];
-	const previousMaxHp = target.maxHp;
-	const previousCurrentHp = target.currentHp;
+	const previousMaxHp = found.combatant.maxHp;
+	const previousCurrentHp = found.combatant.currentHp;
 
 	let newMaxHp: number | undefined;
 	let newCurrentHp: number | undefined;

packages/domain/src/set-initiative.ts

@@ -1,6 +1,12 @@
 import type { DomainEvent } from "./events.js";
 import { sortByInitiative } from "./initiative-sort.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface SetInitiativeSuccess {
 	readonly encounter: Encounter;
@@ -24,15 +30,8 @@ export function setInitiative(
 	combatantId: CombatantId,
 	value: number | undefined,
 ): SetInitiativeSuccess | DomainError {
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
 
 	if (value !== undefined && !Number.isInteger(value)) {
 		return {
@@ -42,8 +41,7 @@ export function setInitiative(
 		};
 	}
 
-	const target = encounter.combatants[targetIdx];
-	const previousValue = target.initiative;
+	const previousValue = found.combatant.initiative;
 
 	// Create new combatants array with updated initiative
 	const updated = encounter.combatants.map((c) =>

packages/domain/src/set-temp-hp.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface SetTempHpSuccess {
 	readonly encounter: Encounter;
@@ -18,17 +24,9 @@ export function setTempHp(
 	combatantId: CombatantId,
 	tempHp: number | undefined,
 ): SetTempHpSuccess | DomainError {
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
-
-	const target = encounter.combatants[targetIdx];
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
+	const { combatant: target } = found;
 
 	if (target.maxHp === undefined || target.currentHp === undefined) {
 		return {

packages/domain/src/toggle-concentration.ts

@@ -1,5 +1,11 @@
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface ToggleConcentrationSuccess {
 	readonly encounter: Encounter;
@@ -10,17 +16,9 @@ export function toggleConcentration(
 	encounter: Encounter,
 	combatantId: CombatantId,
 ): ToggleConcentrationSuccess | DomainError {
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
-
-	const target = encounter.combatants[targetIdx];
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
+	const { combatant: target } = found;
 	const wasConcentrating = target.isConcentrating === true;
 
 	const event: DomainEvent = wasConcentrating

packages/domain/src/toggle-condition.ts

@@ -1,7 +1,13 @@
 import type { ConditionId } from "./conditions.js";
 import { CONDITION_DEFINITIONS, VALID_CONDITION_IDS } from "./conditions.js";
 import type { DomainEvent } from "./events.js";
-import type { CombatantId, DomainError, Encounter } from "./types.js";
+import {
+	type CombatantId,
+	type DomainError,
+	type Encounter,
+	findCombatant,
+	isDomainError,
+} from "./types.js";
 
 export interface ToggleConditionSuccess {
 	readonly encounter: Encounter;
@@ -21,17 +27,9 @@ export function toggleCondition(
 		};
 	}
 
-	const targetIdx = encounter.combatants.findIndex((c) => c.id === combatantId);
-
-	if (targetIdx === -1) {
-		return {
-			kind: "domain-error",
-			code: "combatant-not-found",
-			message: `No combatant found with ID "${combatantId}"`,
-		};
-	}
-
-	const target = encounter.combatants[targetIdx];
+	const found = findCombatant(encounter, combatantId);
+	if (isDomainError(found)) return found;
+	const { combatant: target } = found;
 	const current = target.conditions ?? [];
 	const isActive = current.includes(conditionId);
 

packages/domain/src/types.ts

@@ -70,6 +70,20 @@ export function createEncounter(
 	return { combatants, activeIndex, roundNumber };
 }
 
+export function findCombatant(
+	encounter: Encounter,
+	id: CombatantId,
+): { index: number; combatant: Combatant } | DomainError {
+	const index = encounter.combatants.findIndex((c) => c.id === id);
+	if (index === -1) {
+		return domainError(
+			"combatant-not-found",
+			`No combatant found with ID "${id}"`,
+		);
+	}
+	return { index, combatant: encounter.combatants[index] };
+}
+
 export function isDomainError(value: unknown): value is DomainError {
 	return (
 		typeof value === "object" &&