fix: tighten as any usage in performanceShim and clarify fileHistory cap

- performanceShim: replace 'as any' on the onresourcetimingbufferfull
  getter/setter and the globalThis install guard with typed intersection
  casts, per the project's TS guideline.
- fileHistory: clarify the MAX_SNAPSHOTS comment so it reflects that
  checkpointing is throttled (cap reduced from 100 to 20), not disabled.

scripts/dev.ts

@@ -14,11 +14,20 @@ const __dirname = dirname(__filename)
 const projectRoot = join(__dirname, '..')
 const cliPath = join(projectRoot, 'src/entrypoints/cli.tsx')
 
+// React production mode — prevents 6,889+ _debugStack Error objects
+// (12MB) from accumulating during long-running sessions.
+// Opt-in via CLAUDE_CODE_FORCE_NODE_ENV=production for dev sessions that
+// need the memory optimization. Default keeps NODE_ENV='development' so
+// dev-only diagnostics (DevBar, doctorDiagnostic, AutoUpdater dev branches,
+// etc.) continue to work.
+const forcedNodeEnv =
+  process.env.CLAUDE_CODE_FORCE_NODE_ENV ??
+  process.env.NODE_ENV ??
+  'development'
+
 const defines = {
   ...getMacroDefines(),
-  // React production mode — prevents 6,889+ _debugStack Error objects
+  'process.env.NODE_ENV': JSON.stringify(forcedNodeEnv),
-  // (12MB) from accumulating during long-running sessions.
-  'process.env.NODE_ENV': JSON.stringify('production'),
 }
 
 const defineArgs = Object.entries(defines).flatMap(([k, v]) => [

src/screens/REPL.tsx

@@ -4937,7 +4937,7 @@ export function REPL({
   useMailboxBridge({ isLoading, onSubmitMessage: handleIncomingPrompt });
   useMasterMonitor();
   useSlaveNotifications();
-  const _pipeIpcState = useAppState(s => getPipeIpc(s as any));
+  const _pipeIpcState = useAppState(s => getPipeIpc(s));
 
   usePipePermissionForward({ store, tools, setMessages, setToolUseConfirmQueue, getToolUseContext, mainLoopModel });
   usePipeMuteSync({ setToolUseConfirmQueue });

src/services/api/gemini/index.ts

@@ -6,7 +6,7 @@ import type {
   StreamEvent,
   SystemAPIErrorMessage,
 } from '../../../types/message.js'
-import { type Tools } from '../../../Tool.js'
+import type { Tools } from 'src/Tool.js'
 import { toolToAPISchema } from '../../../utils/api.js'
 import { logForDebugging } from '../../../utils/debug.js'
 import {

src/utils/fileHistory.ts

@@ -51,8 +51,9 @@ export type FileHistoryState = {
   snapshotSequence: number
 }
 
-// Disabled: file checkpointing causes unbounded memory growth (100 snapshots × full file backups).
+// Throttled: file checkpointing remains enabled (gated by fileHistoryEnabled())
-// See heap snapshot analysis — re-enable only after switching to incremental diffs.
+// but capped to mitigate unbounded memory growth (full file backups x N snapshots).
+// See heap snapshot analysis; only raise this cap after switching to incremental diffs.
 const MAX_SNAPSHOTS = 20
 export type DiffStats =
   | {

src/utils/performanceShim.ts

@@ -105,6 +105,10 @@ function getEntriesByName(name: string, type?: string): PerformanceEntryLike[] {
   return entries.filter(e => e.name === name)
 }
 
+function getEntries(): PerformanceEntryLike[] {
+  return [...getEntriesByType('mark'), ...getEntriesByType('measure')]
+}
+
 function clearMarks(name?: string): void {
   if (name !== undefined) {
     marks.delete(name)
@@ -128,6 +132,7 @@ const shim = {
   now,
   mark,
   measure: measure as typeof performance.measure,
+  getEntries: getEntries as typeof performance.getEntries,
   getEntriesByType: getEntriesByType as typeof performance.getEntriesByType,
   getEntriesByName: getEntriesByName as typeof performance.getEntriesByName,
   clearMarks: clearMarks as typeof performance.clearMarks,
@@ -140,10 +145,11 @@ const shim = {
     return original.timeOrigin
   },
   get onresourcetimingbufferfull() {
-    return (original as any).onresourcetimingbufferfull
+    return (original as Performance & { onresourcetimingbufferfull?: unknown })
+      .onresourcetimingbufferfull
   },
-  set onresourcetimingbufferfull(_v: any) {
+  set onresourcetimingbufferfull(_v: unknown) {
-    // no-op — prevent accumulation
+    // no-op to prevent accumulation
   },
   toJSON() {
     return original.toJSON()
@@ -156,8 +162,11 @@ const shim = {
  * native Performance reference.
  */
 export function installPerformanceShim(): void {
-  if ((globalThis as any).__performanceShimInstalled) return
+  const g = globalThis as typeof globalThis & {
-  ;(globalThis as any).__performanceShimInstalled = true
+    __performanceShimInstalled?: boolean
+  }
+  if (g.__performanceShimInstalled) return
+  g.__performanceShimInstalled = true
   globalThis.performance = shim
 }