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/useSessionCache.ts

@@ -0,0 +1,99 @@
+import { createEffect, createSignal, type Accessor } from "solid-js"
+import { messageStoreBus } from "../../../stores/message-v2/bus"
+import { clearSessionRenderCache } from "../../message-block"
+import { getLogger } from "../../../lib/logger"
+
+const log = getLogger("session")
+
+const SESSION_CACHE_LIMIT = 5
+
+type SessionCacheOptions = {
+  instanceId: Accessor<string>
+  instanceSessions: Accessor<Map<string, unknown>>
+  activeSessionId: Accessor<string | null>
+}
+
+type SessionCacheState = {
+  cachedSessionIds: Accessor<string[]>
+}
+
+export function useSessionCache(options: SessionCacheOptions): SessionCacheState {
+  const [cachedSessionIds, setCachedSessionIds] = createSignal<string[]>([])
+  const [pendingEvictions, setPendingEvictions] = createSignal<string[]>([])
+
+  const evictSession = (sessionId: string) => {
+    if (!sessionId) return
+    const instanceId = options.instanceId()
+    log.info("Evicting cached session", { instanceId, sessionId })
+    const store = messageStoreBus.getInstance(instanceId)
+    store?.clearSession(sessionId)
+    clearSessionRenderCache(instanceId, sessionId)
+  }
+
+  const scheduleEvictions = (ids: string[]) => {
+    if (!ids.length) return
+    setPendingEvictions((current) => {
+      const existing = new Set(current)
+      const next = [...current]
+      ids.forEach((id) => {
+        if (!existing.has(id)) {
+          next.push(id)
+          existing.add(id)
+        }
+      })
+      return next
+    })
+  }
+
+  createEffect(() => {
+    const pending = pendingEvictions()
+    if (!pending.length) return
+    const cached = new Set(cachedSessionIds())
+    const remaining: string[] = []
+    pending.forEach((id) => {
+      if (cached.has(id)) {
+        remaining.push(id)
+      } else {
+        evictSession(id)
+      }
+    })
+    if (remaining.length !== pending.length) {
+      setPendingEvictions(remaining)
+    }
+  })
+
+  createEffect(() => {
+    const instanceSessions = options.instanceSessions()
+    const activeId = options.activeSessionId()
+
+    setCachedSessionIds((current) => {
+      const next = current.filter((id) => id !== "info" && instanceSessions.has(id))
+
+      const touch = (id: string | null) => {
+        if (!id || id === "info") return
+        if (!instanceSessions.has(id)) return
+
+        const index = next.indexOf(id)
+        if (index !== -1) {
+          next.splice(index, 1)
+        }
+        next.unshift(id)
+      }
+
+      touch(activeId)
+
+      const trimmed = next.length > SESSION_CACHE_LIMIT ? next.slice(0, SESSION_CACHE_LIMIT) : next
+
+      const trimmedSet = new Set(trimmed)
+      const removed = current.filter((id) => !trimmedSet.has(id))
+      if (removed.length) {
+        scheduleEvictions(removed)
+      }
+      return trimmed
+    })
+  })
+
+  return {
+    cachedSessionIds,
+  }
+}