refactor: add main.ts decomposition guardrails and extract core helpers

src/core/utils/keybindings.ts

@@ -0,0 +1,30 @@
+import { Config, Keybinding } from "../../types";
+
+export function resolveKeybindings(
+  config: Config,
+  defaultKeybindings: Keybinding[],
+): Keybinding[] {
+  const userBindings = config.keybindings || [];
+  const bindingMap = new Map<string, (string | number)[] | null>();
+
+  for (const binding of defaultKeybindings) {
+    bindingMap.set(binding.key, binding.command);
+  }
+
+  for (const binding of userBindings) {
+    if (binding.command === null) {
+      bindingMap.delete(binding.key);
+    } else {
+      bindingMap.set(binding.key, binding.command);
+    }
+  }
+
+  const keybindings: Keybinding[] = [];
+  for (const [key, command] of bindingMap) {
+    if (command !== null) {
+      keybindings.push({ key, command });
+    }
+  }
+
+  return keybindings;
+}