refactor: extract various constants

frontend/src/app/PanelManagerContext.tsx

@@ -10,13 +10,16 @@ import React, {
 } from 'react';
 import type { CSSProperties, PointerEvent as ReactPointerEvent, RefObject } from 'react';
 import { useSidebarContext } from '../sidebar/SidebarContext';
-
-type PanelKey = 'sidebar' | 'detail';
-
-interface PanelLimits {
-  maxRatio: number;
-  minPx: number;
-}
+import {
+  DEFAULT_DETAIL_WIDTH,
+  DEFAULT_SIDEBAR_WIDTH,
+  MINIMAL_FREE_RATIO,
+  MINIMUM_MAIN_CONTENT_WIDTH,
+  PANEL_LIMITS,
+  PANEL_STORAGE_KEYS,
+  SIDEBAR_SOLO_THRESHOLD,
+  type PanelKey,
+} from '../constants/layout';
 
 interface SetPanelWidthOptions {
   commit?: boolean;
@@ -50,29 +53,6 @@ type PanelResizeBindings = {
 
 const PanelManagerContext = createContext<PanelManagerContextValue | null>(null);
 
-const PANEL_LIMITS: Record<PanelKey, PanelLimits> = {
-  sidebar: {
-    maxRatio: 1 / 3,
-    minPx: 280,
-  },
-  detail: {
-    maxRatio: 2 / 3,
-    minPx: 320,
-  },
-};
-
-const STORAGE_KEYS: Record<PanelKey, string> = {
-  sidebar: 'papercrate_sidebar_width',
-  detail: 'papercrate_detail_width',
-};
-
-const DEFAULT_SIDEBAR_WIDTH = 320;
-const DEFAULT_DETAIL_WIDTH = 420;
-
-const MINIMAL_FREE_RATIO = 1 / 3;
-const SIDEBAR_SOLO_THRESHOLD = 1 / 2;
-const MINIMUM_MAIN_CONTENT_WIDTH = 160;
-
 const clampPanelWidth = (panel: PanelKey, value: number): number => {
   const numeric = Number(value);
   const limits = PANEL_LIMITS[panel];
@@ -86,7 +66,7 @@ const clampPanelWidth = (panel: PanelKey, value: number): number => {
 };
 
 const readStoredWidth = (panel: PanelKey, fallback: number): number => {
-  const raw = window.localStorage.getItem(STORAGE_KEYS[panel]);
+  const raw = window.localStorage.getItem(PANEL_STORAGE_KEYS[panel]);
   if (!raw) {
     return fallback;
   }
@@ -95,7 +75,7 @@ const readStoredWidth = (panel: PanelKey, fallback: number): number => {
 };
 
 const persistWidth = (panel: PanelKey, value: number): void => {
-  window.localStorage.setItem(STORAGE_KEYS[panel], String(Math.round(value)));
+  window.localStorage.setItem(PANEL_STORAGE_KEYS[panel], String(Math.round(value)));
 };
 
 const applyPanelWidthToRoot = (panel: PanelKey, width: number, active: boolean): void => {