feat(ui): add new session icon in sidebar header

fix(ui): handle Windows paths in instance tab titles

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

@@ -11,20 +11,11 @@ interface InstanceTabProps {
   onClose: () => void
 }
 
-function formatFolderName(path: string, instances: Instance[], currentInstance: Instance): string {
-  const name = path.split("/").pop() || path
-
-  const duplicates = instances.filter((i) => {
-    const iName = i.folder.split("/").pop() || i.folder
-    return iName === name
-  })
-
-  if (duplicates.length > 1) {
-    const index = duplicates.findIndex((i) => i.id === currentInstance.id)
-    return `~/${name} (${index + 1})`
-  }
-
-  return `~/${name}`
+function getPathBasename(path: string): string {
+  // Instance folders can be POSIX-like (/Users/...) on macOS/Linux or Windows-like (C:\Users\...).
+  // Normalize by trimming trailing separators and then splitting on both '/' and '\\'.
+  const normalized = path.replace(/[\\/]+$/, "")
+  return normalized.split(/[\\/]/).pop() || path
 }
 
 const InstanceTab: Component<InstanceTabProps> = (props) => {
@@ -58,7 +49,7 @@ const InstanceTab: Component<InstanceTabProps> = (props) => {
       >
         <FolderOpen class="w-4 h-4 flex-shrink-0" />
         <span class="tab-label">
-          {props.instance.folder.split("/").pop() || props.instance.folder}
+          {getPathBasename(props.instance.folder)}
         </span>
         <span
           class={`status-indicator session-status ml-auto ${statusClassName()}`}

packages/ui/src/components/instance/shell/SessionSidebar.tsx

@@ -4,7 +4,7 @@ import type { Session } from "../../../types/session"
 import type { KeyboardShortcut } from "../../../lib/keyboard-registry"
 import type { DrawerViewState } from "./types"
 
-import { Search } from "lucide-solid"
+import { Search, SquarePlus } from "lucide-solid"
 import IconButton from "@suid/material/IconButton"
 import MenuOpenIcon from "@suid/icons-material/MenuOpen"
 import PushPinIcon from "@suid/icons-material/PushPin"
@@ -56,6 +56,20 @@ const SessionSidebar: Component<SessionSidebarProps> = (props) => (
           {props.t("instanceShell.leftPanel.sessionsTitle")}
         </span>
         <div class="flex items-center gap-2 text-primary">
+          <IconButton
+            size="small"
+            color="inherit"
+            aria-label={props.t("sessionList.actions.newSession.ariaLabel")}
+            title={props.t("sessionList.actions.newSession.title")}
+            onClick={() => {
+              const result = props.onNewSession()
+              if (result instanceof Promise) {
+                void result.catch((error) => log.error("Failed to create session:", error))
+              }
+            }}
+          >
+            <SquarePlus class="w-4 h-4 opacity-70" />
+          </IconButton>
           <IconButton
             size="small"
             color="inherit"

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

@@ -21,6 +21,8 @@ export const sessionMessages = {
   "sessionList.expand.expandAriaLabel": "Expand session",
   "sessionList.expand.collapseTitle": "Collapse",
   "sessionList.expand.expandTitle": "Expand",
+  "sessionList.actions.newSession.ariaLabel": "New session",
+  "sessionList.actions.newSession.title": "New session",
   "sessionList.actions.copyId.ariaLabel": "Copy session ID",
   "sessionList.actions.copyId.title": "Copy session ID",
   "sessionList.actions.rename.ariaLabel": "Rename session",

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

@@ -21,6 +21,8 @@ export const sessionMessages = {
   "sessionList.expand.expandAriaLabel": "Expandir sesión",
   "sessionList.expand.collapseTitle": "Colapsar",
   "sessionList.expand.expandTitle": "Expandir",
+  "sessionList.actions.newSession.ariaLabel": "Nueva sesión",
+  "sessionList.actions.newSession.title": "Nueva sesión",
   "sessionList.actions.copyId.ariaLabel": "Copiar ID de sesión",
   "sessionList.actions.copyId.title": "Copiar ID de sesión",
   "sessionList.actions.rename.ariaLabel": "Renombrar sesión",

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

@@ -21,6 +21,8 @@ export const sessionMessages = {
   "sessionList.expand.expandAriaLabel": "Développer la session",
   "sessionList.expand.collapseTitle": "Réduire",
   "sessionList.expand.expandTitle": "Développer",
+  "sessionList.actions.newSession.ariaLabel": "Nouvelle session",
+  "sessionList.actions.newSession.title": "Nouvelle session",
   "sessionList.actions.copyId.ariaLabel": "Copier l'ID de session",
   "sessionList.actions.copyId.title": "Copier l'ID de session",
   "sessionList.actions.rename.ariaLabel": "Renommer la session",

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

@@ -21,6 +21,8 @@ export const sessionMessages = {
   "sessionList.expand.expandAriaLabel": "セッションを展開",
   "sessionList.expand.collapseTitle": "折りたたむ",
   "sessionList.expand.expandTitle": "展開",
+  "sessionList.actions.newSession.ariaLabel": "新しいセッション",
+  "sessionList.actions.newSession.title": "新しいセッション",
   "sessionList.actions.copyId.ariaLabel": "セッション ID をコピー",
   "sessionList.actions.copyId.title": "セッション ID をコピー",
   "sessionList.actions.rename.ariaLabel": "セッション名を変更",

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

@@ -21,6 +21,8 @@ export const sessionMessages = {
   "sessionList.expand.expandAriaLabel": "Развернуть сессию",
   "sessionList.expand.collapseTitle": "Свернуть",
   "sessionList.expand.expandTitle": "Развернуть",
+  "sessionList.actions.newSession.ariaLabel": "Новая сессия",
+  "sessionList.actions.newSession.title": "Новая сессия",
   "sessionList.actions.copyId.ariaLabel": "Скопировать ID сессии",
   "sessionList.actions.copyId.title": "Скопировать ID сессии",
   "sessionList.actions.rename.ariaLabel": "Переименовать сессию",

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

@@ -21,6 +21,8 @@ export const sessionMessages = {
   "sessionList.expand.expandAriaLabel": "展开会话",
   "sessionList.expand.collapseTitle": "折叠",
   "sessionList.expand.expandTitle": "展开",
+  "sessionList.actions.newSession.ariaLabel": "新建会话",
+  "sessionList.actions.newSession.title": "新建会话",
   "sessionList.actions.copyId.ariaLabel": "复制会话 ID",
   "sessionList.actions.copyId.title": "复制会话 ID",
   "sessionList.actions.rename.ariaLabel": "重命名会话",

packages/ui/src/styles/markdown.css

@@ -1,4 +1,4 @@
-@import "github-markdown-css/github-markdown-light.css" layer(github-markdown-base);
+@import "github-markdown-css/github-markdown-dark.css";
 
 @layer components {
   .markdown-body {
@@ -96,7 +96,6 @@
   .markdown-body code {
     font-family: var(--font-family-mono);
     font-size: var(--font-size-sm);
-    color: var(--text-primary);
     background-color: var(--surface-muted);
     border: 1px solid var(--border-base);
     border-radius: 4px;
@@ -109,23 +108,17 @@
     background: transparent;
   }
 
-  .markdown-body pre:not(.shiki) {
+  .markdown-body pre {
     font-family: var(--font-family-mono);
     font-size: var(--font-size-sm);
     line-height: var(--line-height-normal);
     background-color: var(--surface-code);
-    color: var(--text-primary);
     border: 1px solid var(--border-base);
     border-radius: 8px;
     padding: 0.75rem;
     margin: 1rem 0;
   }
 
-  .markdown-body pre:not(.shiki) code,
-  .markdown-code-block pre:not(.shiki) code {
-    color: var(--text-primary);
-  }
-
   .markdown-body blockquote {
     border-left: 3px solid var(--border-base);
     color: var(--text-secondary);
@@ -175,18 +168,12 @@
     border: 1px solid var(--border-base);
     padding: 0.5rem 0.75rem;
     text-align: left;
-    color: var(--text-primary);
-    background-color: transparent;
   }
 
   .markdown-body th {
     background-color: var(--surface-secondary);
   }
 
-  .markdown-body tbody tr:nth-child(2n) {
-    background-color: var(--surface-muted);
-  }
-
   .markdown-code-block {
     position: relative;
     margin: 10px 0;