refactor: 拆分 cockpit 為可個別安裝的 statusbar 與 companion

- statusbar：輸入框上方狀態列，指令 /statusbar
- companion：小說角色陪伴，指令 /companion，自行渲染角色行
- companion 資料目錄改為 ~/.companion
- 整併 M4 檔案至 companion；M2 實作移至 hooks/companion/persona
- README 移除本機資料夾安裝，補上更新與移除指令

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

plugins/companion/hooks/companion/band.ts

@@ -0,0 +1,33 @@
+import { bar, lineWidth } from './seg'
+import type { Seg } from './seg'
+import type { View } from './core'
+
+const axis = (v: number) => bar(((v + 1) / 2) * 100, 3)
+
+// 由完整版往下捨棄次要資訊：氣泡 → 待辦 → PAD 條 → 好感階段；緊湊版只留「顏文字 名字 心情」
+function line(v: View, level: number, compact: boolean, bubble?: string): Seg[] {
+  const out: Seg[] = [
+    { text: `${v.kaomoji} `, color: 'claude' },
+    { text: v.core.name, bold: true },
+    { text: ' ' },
+    { text: v.label, color: 'suggestion' },
+  ]
+  if (compact) return out
+  const dot = { text: ' · ', dim: true }
+  if (level < 3) out.push(dot, { text: `P${axis(v.mood.p)} A${axis(v.mood.a)} D${axis(v.mood.d)}`, dim: true })
+  if (level < 4) out.push(dot, { text: v.stage })
+  if (level < 2 && v.todos > 0) out.push(dot, { text: `☐${v.todos}`, color: 'warning' })
+  if (level < 1 && bubble) out.push(dot, { text: `💬 ${bubble}`, dim: true })
+  return out
+}
+
+export const COMPANION_MAX_LEVEL = 4
+
+export function fitCompanion(v: View, columns: number, compact = false, bubble?: string): Seg[] {
+  if (compact) return line(v, 0, true)
+  for (let level = 0; level <= COMPANION_MAX_LEVEL; level++) {
+    const l = line(v, level, false, bubble)
+    if (lineWidth(l) <= columns) return l
+  }
+  return line(v, 0, true)
+}