feat(effort): 新增 EffortPanel 纯函数状态模块（PanelPosition + 移动/初始光标）

仅含纯函数与类型，无 React/Ink 依赖，便于单测。
- PANEL_POSITIONS：low → medium → high → xhigh → max → ultracode
- moveLeft/moveRight：边界钳制（low 不再左移、ultracode 不再右移）
- getInitialCursor：env override > displayed level

Co-Authored-By: glm-5.2 <zai-org@claude-code-best.win>

src/components/EffortPanel/__tests__/effortPanelState.test.ts

@@ -0,0 +1,101 @@
+import { describe, expect, test } from 'bun:test'
+import {
+  END_POSITION,
+  HOME_POSITION,
+  PANEL_POSITIONS,
+  type PanelPosition,
+  getInitialCursor,
+  isUltracode,
+  moveLeft,
+  moveRight,
+} from '../effortPanelState.js'
+
+describe('effortPanelState', () => {
+  test('PANEL_POSITIONS 顺序为 low → ultracode', () => {
+    expect(PANEL_POSITIONS).toEqual([
+      'low',
+      'medium',
+      'high',
+      'xhigh',
+      'max',
+      'ultracode',
+    ])
+  })
+
+  test('moveLeft 在 low 处保持 low', () => {
+    expect(moveLeft('low')).toBe('low')
+  })
+
+  test('moveLeft 正常左移', () => {
+    expect(moveLeft('high')).toBe('medium')
+    expect(moveLeft('ultracode')).toBe('max')
+  })
+
+  test('moveRight 在 ultracode 处保持 ultracode', () => {
+    expect(moveRight('ultracode')).toBe('ultracode')
+  })
+
+  test('moveRight 正常右移', () => {
+    expect(moveRight('medium')).toBe('high')
+    expect(moveRight('max')).toBe('ultracode')
+  })
+
+  test('HOME_POSITION 等于 low', () => {
+    expect(HOME_POSITION).toBe('low')
+  })
+
+  test('END_POSITION 等于 ultracode', () => {
+    expect(END_POSITION).toBe('ultracode')
+  })
+
+  test('isUltracode 守卫', () => {
+    expect(isUltracode('ultracode')).toBe(true)
+    expect(isUltracode('max')).toBe(false)
+  })
+
+  test('getInitialCursor：env override 为合法档位时返回 env 值', () => {
+    expect(
+      getInitialCursor({
+        envOverride: 'high',
+        appStateEffort: 'medium',
+        displayed: 'high',
+      }),
+    ).toBe('high')
+  })
+
+  test('getInitialCursor：env 为 null（unset）时用 displayed', () => {
+    expect(
+      getInitialCursor({
+        envOverride: null,
+        appStateEffort: undefined,
+        displayed: 'medium',
+      }),
+    ).toBe('medium')
+  })
+
+  test('getInitialCursor：env undefined 时用 displayed', () => {
+    expect(
+      getInitialCursor({
+        envOverride: undefined,
+        appStateEffort: 'high',
+        displayed: 'high',
+      }),
+    ).toBe('high')
+  })
+
+  test('getInitialCursor：env 是数值（ant-only）时落回 displayed', () => {
+    // 数值不是合法 PanelPosition，回退
+    expect(
+      getInitialCursor({
+        envOverride: 75,
+        appStateEffort: 'medium',
+        displayed: 'medium',
+      }),
+    ).toBe('medium')
+  })
+
+  test('PanelPosition 类型编译期检查（隐式）', () => {
+    const p: PanelPosition = 'xhigh'
+    expect(p).toBe('xhigh')
+  })
+})

src/components/EffortPanel/effortPanelState.ts

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+import type { EffortValue } from '../../utils/effort.js'
+
+/**
+ * 光标在面板上的位置。仅面板内部使用，不进入 AppState / settings / API。
+ * 'ultracode' 不是 EffortLevel；它在本面板里仅作视觉占位与文案引导。
+ */
+export type PanelPosition =
+  | 'low'
+  | 'medium'
+  | 'high'
+  | 'xhigh'
+  | 'max'
+  | 'ultracode'
+
+export const PANEL_POSITIONS: readonly PanelPosition[] = [
+  'low',
+  'medium',
+  'high',
+  'xhigh',
+  'max',
+  'ultracode',
+] as const
+
+export const HOME_POSITION: PanelPosition = 'low'
+export const END_POSITION: PanelPosition = 'ultracode'
+
+/**
+ * 判断一个值是否可作为面板光标位置（不含 ultracode，因 ultracode 仅由面板内部产生）。
+ */
+function isNonUltracodePosition(
+  value: unknown,
+): value is Exclude<PanelPosition, 'ultracode'> {
+  return (
+    typeof value === 'string' &&
+    value !== 'ultracode' &&
+    (PANEL_POSITIONS as readonly string[]).includes(value)
+  )
+}
+
+/**
+ * 把 EffortValue 归一化为面板可用的光标位置。
+ * - null / undefined / 数值（ant-only）/ ultracode → undefined（让上层用 displayed）
+ * - 合法 string 档位 → 返回该档位
+ */
+function normalizeToPanelPosition(
+  value: EffortValue | null | undefined,
+): PanelPosition | undefined {
+  if (value === null || value === undefined) return undefined
+  if (typeof value === 'number') return undefined
+  if (isNonUltracodePosition(value)) {
+    return value
+  }
+  return undefined
+}
+
+export function moveLeft(cursor: PanelPosition): PanelPosition {
+  const idx = PANEL_POSITIONS.indexOf(cursor)
+  if (idx <= 0) return PANEL_POSITIONS[0]
+  return PANEL_POSITIONS[idx - 1]
+}
+
+export function moveRight(cursor: PanelPosition): PanelPosition {
+  const idx = PANEL_POSITIONS.indexOf(cursor)
+  if (idx === -1 || idx >= PANEL_POSITIONS.length - 1) {
+    return PANEL_POSITIONS[PANEL_POSITIONS.length - 1]
+  }
+  return PANEL_POSITIONS[idx + 1]
+}
+
+export function isUltracode(cursor: PanelPosition): boolean {
+  return cursor === 'ultracode'
+}
+
+/**
+ * 决定面板挂载时的初始光标位置。
+ * 优先级：env override（若是合法档位）> displayed level
+ *
+ * @param envOverride    getEffortEnvOverride() 的返回值：EffortValue | null | undefined
+ * @param appStateEffort AppState.effortValue
+ * @param displayed      getDisplayedEffortLevel(model, appStateEffort) —— 必传，避免此处再依赖 model
+ */
+export function getInitialCursor(args: {
+  envOverride: EffortValue | null | undefined
+  appStateEffort: EffortValue | undefined
+  displayed: PanelPosition
+}): PanelPosition {
+  const fromEnv = normalizeToPanelPosition(args.envOverride)
+  if (fromEnv !== undefined) return fromEnv
+  // displayed 已经是 EffortLevel（不含 ultracode），合法
+  return args.displayed
+}