feat(ui): add Session Changes sidebar section

Show session-level file changes in the right drawer with per-file +additions/-deletions and a Show changes button that appears only when diffs exist.

packages/ui/src/components/instance/instance-shell2.tsx

@@ -304,6 +304,11 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
     return activeSessions().get(sessionId) ?? null
   })
 
+  const activeSessionDiffs = createMemo(() => {
+    const session = activeSessionForInstance()
+    return session?.diff
+  })
+
   const activeSessionUsage = createMemo(() => {
     const sessionId = activeSessionIdForInstance()
     if (!sessionId) return null
@@ -960,6 +965,70 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
   )
 
   const RightDrawerContent = () => {
+    const renderSessionChanges = () => {
+      const sessionId = activeSessionIdForInstance()
+      if (!sessionId || sessionId === "info") {
+        return <p class="text-xs text-secondary">{t("instanceShell.sessionChanges.noSessionSelected")}</p>
+      }
+
+      const diffs = activeSessionDiffs()
+      if (diffs === undefined) {
+        return <p class="text-xs text-secondary">{t("instanceShell.sessionChanges.loading")}</p>
+      }
+
+      if (!Array.isArray(diffs) || diffs.length === 0) {
+        return <p class="text-xs text-secondary">{t("instanceShell.sessionChanges.empty")}</p>
+      }
+
+      const sorted = [...diffs].sort((a, b) => String(a.file || "").localeCompare(String(b.file || "")))
+      const totals = sorted.reduce(
+        (acc, item) => {
+          acc.additions += typeof item.additions === "number" ? item.additions : 0
+          acc.deletions += typeof item.deletions === "number" ? item.deletions : 0
+          return acc
+        },
+        { additions: 0, deletions: 0 },
+      )
+
+      return (
+        <div class="flex flex-col gap-3 min-h-0">
+          <div class="flex items-center justify-between gap-2 text-[11px] text-secondary">
+            <span>{t("instanceShell.sessionChanges.filesChanged", { count: sorted.length })}</span>
+            <span class="flex items-center gap-2">
+              <span style={{ color: "var(--session-status-idle-fg)" }}>{`+${totals.additions}`}</span>
+              <span style={{ color: "var(--session-status-working-fg)" }}>{`-${totals.deletions}`}</span>
+            </span>
+          </div>
+
+          <div class="rounded-md border border-base bg-surface-secondary p-2 max-h-[40vh] overflow-y-auto">
+            <div class="flex flex-col">
+              <For each={sorted}>
+                {(item) => (
+                  <div class="py-2 border-b border-base last:border-b-0">
+                    <div class="text-xs font-mono text-primary truncate" title={item.file}>
+                      {item.file}
+                    </div>
+                    <div class="flex items-center gap-2 text-[11px]">
+                      <span style={{ color: "var(--session-status-idle-fg)" }}>{`+${item.additions}`}</span>
+                      <span style={{ color: "var(--session-status-working-fg)" }}>{`-${item.deletions}`}</span>
+                    </div>
+                  </div>
+                )}
+              </For>
+            </div>
+          </div>
+
+          <button
+            type="button"
+            class="button-tertiary w-full p-1.5 inline-flex items-center justify-center"
+            onClick={() => undefined}
+          >
+            {t("instanceShell.sessionChanges.actions.show")}
+          </button>
+        </div>
+      )
+    }
+
     const renderPlanSectionContent = () => {
       const sessionId = activeSessionIdForInstance()
       if (!sessionId || sessionId === "info") {
@@ -1034,6 +1103,11 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
     }
 
     const sections = [
+      {
+        id: "session-changes",
+        labelKey: "instanceShell.rightPanel.sections.sessionChanges",
+        render: renderSessionChanges,
+      },
       {
         id: "plan",
         labelKey: "instanceShell.rightPanel.sections.plan",

packages/ui/src/lib/i18n/messages/en/instance.ts

@@ -86,12 +86,19 @@ export const instanceMessages = {
   "instanceShell.empty.description": "Select a session to view messages",
 
   "instanceShell.rightPanel.title": "Status Panel",
+  "instanceShell.rightPanel.sections.sessionChanges": "Session Changes",
   "instanceShell.rightPanel.sections.plan": "Plan",
   "instanceShell.rightPanel.sections.backgroundProcesses": "Background Shells",
   "instanceShell.rightPanel.sections.mcp": "MCP Servers",
   "instanceShell.rightPanel.sections.lsp": "LSP Servers",
   "instanceShell.rightPanel.sections.plugins": "Plugins",
 
+  "instanceShell.sessionChanges.noSessionSelected": "Select a session to view changes.",
+  "instanceShell.sessionChanges.loading": "Fetching session changes...",
+  "instanceShell.sessionChanges.empty": "No session changes yet.",
+  "instanceShell.sessionChanges.filesChanged": "{count} files changed",
+  "instanceShell.sessionChanges.actions.show": "Show changes",
+
   "instanceShell.plan.noSessionSelected": "Select a session to view plan.",
   "instanceShell.plan.empty": "Nothing planned yet.",
 

packages/ui/src/lib/i18n/messages/es/instance.ts

@@ -86,12 +86,19 @@ export const instanceMessages = {
   "instanceShell.empty.description": "Selecciona una sesión para ver mensajes",
 
   "instanceShell.rightPanel.title": "Panel de estado",
+  "instanceShell.rightPanel.sections.sessionChanges": "Cambios de sesion",
   "instanceShell.rightPanel.sections.plan": "Plan",
   "instanceShell.rightPanel.sections.backgroundProcesses": "Shells en segundo plano",
   "instanceShell.rightPanel.sections.mcp": "Servidores MCP",
   "instanceShell.rightPanel.sections.lsp": "Servidores LSP",
   "instanceShell.rightPanel.sections.plugins": "Plugins",
 
+  "instanceShell.sessionChanges.noSessionSelected": "Selecciona una sesion para ver los cambios.",
+  "instanceShell.sessionChanges.loading": "Obteniendo cambios de la sesion...",
+  "instanceShell.sessionChanges.empty": "Aun no hay cambios.",
+  "instanceShell.sessionChanges.filesChanged": "{count} archivos cambiados",
+  "instanceShell.sessionChanges.actions.show": "Mostrar cambios",
+
   "instanceShell.plan.noSessionSelected": "Selecciona una sesión para ver el plan.",
   "instanceShell.plan.empty": "Aún no hay nada planificado.",
 

packages/ui/src/lib/i18n/messages/fr/instance.ts

@@ -86,12 +86,19 @@ export const instanceMessages = {
   "instanceShell.empty.description": "Sélectionnez une session pour voir les messages",
 
   "instanceShell.rightPanel.title": "Panneau d'état",
+  "instanceShell.rightPanel.sections.sessionChanges": "Changements de session",
   "instanceShell.rightPanel.sections.plan": "Plan",
   "instanceShell.rightPanel.sections.backgroundProcesses": "Shells en arrière-plan",
   "instanceShell.rightPanel.sections.mcp": "Serveurs MCP",
   "instanceShell.rightPanel.sections.lsp": "Serveurs LSP",
   "instanceShell.rightPanel.sections.plugins": "Plugins",
 
+  "instanceShell.sessionChanges.noSessionSelected": "Sélectionnez une session pour voir les changements.",
+  "instanceShell.sessionChanges.loading": "Récupération des changements...",
+  "instanceShell.sessionChanges.empty": "Aucun changement pour l'instant.",
+  "instanceShell.sessionChanges.filesChanged": "{count} fichiers modifiés",
+  "instanceShell.sessionChanges.actions.show": "Afficher les changements",
+
   "instanceShell.plan.noSessionSelected": "Sélectionnez une session pour voir le plan.",
   "instanceShell.plan.empty": "Aucun plan pour l'instant.",
 

packages/ui/src/lib/i18n/messages/ja/instance.ts

@@ -86,12 +86,19 @@ export const instanceMessages = {
   "instanceShell.empty.description": "メッセージを表示するにはセッションを選択してください",
 
   "instanceShell.rightPanel.title": "ステータスパネル",
+  "instanceShell.rightPanel.sections.sessionChanges": "セッション変更",
   "instanceShell.rightPanel.sections.plan": "計画",
   "instanceShell.rightPanel.sections.backgroundProcesses": "バックグラウンドシェル",
   "instanceShell.rightPanel.sections.mcp": "MCP サーバー",
   "instanceShell.rightPanel.sections.lsp": "LSP サーバー",
   "instanceShell.rightPanel.sections.plugins": "プラグイン",
 
+  "instanceShell.sessionChanges.noSessionSelected": "変更を表示するにはセッションを選択してください。",
+  "instanceShell.sessionChanges.loading": "変更を取得中...",
+  "instanceShell.sessionChanges.empty": "まだ変更はありません。",
+  "instanceShell.sessionChanges.filesChanged": "{count} 個のファイルが変更されました",
+  "instanceShell.sessionChanges.actions.show": "変更を表示",
+
   "instanceShell.plan.noSessionSelected": "計画を表示するにはセッションを選択してください。",
   "instanceShell.plan.empty": "まだ計画はありません。",
 

packages/ui/src/lib/i18n/messages/ru/instance.ts

@@ -86,12 +86,19 @@ export const instanceMessages = {
   "instanceShell.empty.description": "Выберите сессию, чтобы просмотреть сообщения",
 
   "instanceShell.rightPanel.title": "Панель состояния",
+  "instanceShell.rightPanel.sections.sessionChanges": "Изменения сессии",
   "instanceShell.rightPanel.sections.plan": "План",
   "instanceShell.rightPanel.sections.backgroundProcesses": "Фоновые Shell",
   "instanceShell.rightPanel.sections.mcp": "MCP-серверы",
   "instanceShell.rightPanel.sections.lsp": "LSP-серверы",
   "instanceShell.rightPanel.sections.plugins": "Плагины",
 
+  "instanceShell.sessionChanges.noSessionSelected": "Выберите сессию, чтобы просмотреть изменения.",
+  "instanceShell.sessionChanges.loading": "Загрузка изменений...",
+  "instanceShell.sessionChanges.empty": "Пока нет изменений.",
+  "instanceShell.sessionChanges.filesChanged": "Изменено файлов: {count}",
+  "instanceShell.sessionChanges.actions.show": "Показать изменения",
+
   "instanceShell.plan.noSessionSelected": "Выберите сессию, чтобы просмотреть план.",
   "instanceShell.plan.empty": "Пока ничего не запланировано.",
 

packages/ui/src/lib/i18n/messages/zh-Hans/instance.ts

@@ -86,12 +86,19 @@ export const instanceMessages = {
   "instanceShell.empty.description": "选择会话以查看消息",
 
   "instanceShell.rightPanel.title": "状态面板",
+  "instanceShell.rightPanel.sections.sessionChanges": "会话更改",
   "instanceShell.rightPanel.sections.plan": "计划",
   "instanceShell.rightPanel.sections.backgroundProcesses": "后台 Shell",
   "instanceShell.rightPanel.sections.mcp": "MCP 服务器",
   "instanceShell.rightPanel.sections.lsp": "LSP 服务器",
   "instanceShell.rightPanel.sections.plugins": "插件",
 
+  "instanceShell.sessionChanges.noSessionSelected": "选择会话以查看更改。",
+  "instanceShell.sessionChanges.loading": "正在获取会话更改...",
+  "instanceShell.sessionChanges.empty": "暂无会话更改。",
+  "instanceShell.sessionChanges.filesChanged": "已更改 {count} 个文件",
+  "instanceShell.sessionChanges.actions.show": "显示更改",
+
   "instanceShell.plan.noSessionSelected": "选择会话以查看计划。",
   "instanceShell.plan.empty": "暂无计划。",