refactor(ui): modularize instance shell

Split InstanceShell2 into focused shell modules (drawer chrome/resize, session context/cache, sidebar, right panel tabs/components) to improve maintainability while preserving behavior.

packages/ui/src/components/instance/shell/useDrawerResize.ts

@@ -0,0 +1,113 @@
+import { createSignal, onCleanup, type Accessor, type Setter } from "solid-js"
+
+import { useGlobalPointerDrag } from "./useGlobalPointerDrag"
+
+type DrawerResizeSide = "left" | "right"
+
+type DrawerResizeOptions = {
+  sessionSidebarWidth: Accessor<number>
+  rightDrawerWidth: Accessor<number>
+  setSessionSidebarWidth: Setter<number>
+  setRightDrawerWidth: Setter<number>
+  clampLeft: (width: number) => number
+  clampRight: (width: number) => number
+  measureDrawerHost: () => void
+}
+
+type DrawerResizeApi = {
+  handleDrawerResizeMouseDown: (side: DrawerResizeSide) => (event: MouseEvent) => void
+  handleDrawerResizeTouchStart: (side: DrawerResizeSide) => (event: TouchEvent) => void
+}
+
+export function useDrawerResize(options: DrawerResizeOptions): DrawerResizeApi {
+  const [activeResizeSide, setActiveResizeSide] = createSignal<DrawerResizeSide | null>(null)
+  const [resizeStartX, setResizeStartX] = createSignal(0)
+  const [resizeStartWidth, setResizeStartWidth] = createSignal(0)
+
+  const scheduleDrawerMeasure = () => {
+    if (typeof window === "undefined") {
+      options.measureDrawerHost()
+      return
+    }
+    requestAnimationFrame(() => options.measureDrawerHost())
+  }
+
+  const applyDrawerWidth = (side: DrawerResizeSide, width: number) => {
+    if (side === "left") {
+      options.setSessionSidebarWidth(width)
+    } else {
+      options.setRightDrawerWidth(width)
+    }
+    scheduleDrawerMeasure()
+  }
+
+  const handleDrawerPointerMove = (clientX: number) => {
+    const side = activeResizeSide()
+    if (!side) return
+    const startWidth = resizeStartWidth()
+    const clamp = side === "left" ? options.clampLeft : options.clampRight
+    const delta = side === "left" ? clientX - resizeStartX() : resizeStartX() - clientX
+    const nextWidth = clamp(startWidth + delta)
+    applyDrawerWidth(side, nextWidth)
+  }
+
+  function drawerMouseMove(event: MouseEvent) {
+    event.preventDefault()
+    handleDrawerPointerMove(event.clientX)
+  }
+
+  function drawerMouseUp() {
+    stopDrawerResize()
+  }
+
+  function drawerTouchMove(event: TouchEvent) {
+    const touch = event.touches[0]
+    if (!touch) return
+    event.preventDefault()
+    handleDrawerPointerMove(touch.clientX)
+  }
+
+  function drawerTouchEnd() {
+    stopDrawerResize()
+  }
+
+  const drawerPointerDrag = useGlobalPointerDrag({
+    onMouseMove: drawerMouseMove,
+    onMouseUp: drawerMouseUp,
+    onTouchMove: drawerTouchMove,
+    onTouchEnd: drawerTouchEnd,
+  })
+
+  function stopDrawerResize() {
+    setActiveResizeSide(null)
+    drawerPointerDrag.stop()
+  }
+
+  const startDrawerResize = (side: DrawerResizeSide, clientX: number) => {
+    setActiveResizeSide(side)
+    setResizeStartX(clientX)
+    setResizeStartWidth(side === "left" ? options.sessionSidebarWidth() : options.rightDrawerWidth())
+    drawerPointerDrag.start()
+  }
+
+  const handleDrawerResizeMouseDown = (side: DrawerResizeSide) => (event: MouseEvent) => {
+    event.preventDefault()
+    startDrawerResize(side, event.clientX)
+  }
+
+  const handleDrawerResizeTouchStart = (side: DrawerResizeSide) => (event: TouchEvent) => {
+    const touch = event.touches[0]
+    if (!touch) return
+    event.preventDefault()
+    startDrawerResize(side, touch.clientX)
+  }
+
+  onCleanup(() => {
+    stopDrawerResize()
+  })
+
+  return {
+    handleDrawerResizeMouseDown,
+    handleDrawerResizeTouchStart,
+  }
+}