Fix split-pane right-edge resize clipping (#1261)

* fix(app): clamp split pane resize

Prevent right-edge drags from overflowing the Electron viewport.

* fix(app): isolate resize pointer state

Keep concurrent resize drags from clobbering each other.

packages/app/src/stores/workspace-layout-actions.ts

@@ -1,5 +1,6 @@
 import invariant from "tiny-invariant";
 import type { WorkspaceTab, WorkspaceTabTarget } from "@/stores/workspace-tabs-store";
+import { MIN_SPLIT_SIZE } from "@/stores/workspace-layout-constants";
 import { defaultWorkspaceLayoutIds } from "@/stores/workspace-layout-ids";
 import type { WorkspaceLayoutNodeIdPrefix } from "@/stores/workspace-layout-ids";
 import {
@@ -208,7 +209,6 @@ export interface WorkspaceTabSnapshot {
 }
 
 const DEFAULT_PANE_ID = "main";
-const MIN_SPLIT_SIZE = 0.1;
 
 function trimNonEmpty(value: string | null | undefined): string | null {
   if (typeof value !== "string") {

packages/app/src/stores/workspace-layout-constants.ts

@@ -0,0 +1 @@
+export const MIN_SPLIT_SIZE = 0.1;