docs: mention 3 strats for with(Entity)Resource error handling

docs/docs/with-entity-resources.md

@@ -86,6 +86,35 @@ This exposes per-resource members with the resource name as a prefix:
 - **Resource members**: `todosValue()`, `todosStatus()`, `todosError()`, `todosIsLoading()`; `projectsValue()`, ...
 - **Entity members**: `todosIds()`, `todosEntityMap()`, `todosEntities()`; `projectsIds()`, `projectsEntityMap()`, `projectsEntities()`
 
+## Error Handling
+
+Starting in NgRx Toolkit v20.6.0, error handling now has more resilient options.
+
+The behavior of Angular's resources' error handling and the NgRx SignalStore's `getState/patchState` required `withEntityResource` to approach error handling
+with a particular strategy unique to the intersection of resources and the Signal Store.
+To prevent resource failures from blocking the store, the Toolkit provides some strategies to handle errors.
+
+```ts
+withEntityResource(
+  () => ({
+    id: resource({
+      loader: () => Promise.resolve(1),
+      defaultValue: 0,
+    }),
+  }),
+  // Other values: 'native' and 'previous value'
+  { errorHandling: 'undefined value' }, // default if not specified
+),
+```
+
+Options:
+
+1. `'undfined value'` (default). In the event of an error, the resource's value will be `undefined`
+1. `'previous value'`. Provided the resource had a previous value, that previous value will be returned. If not, an error is thrown.
+1. `'native'`. No special handling is provided, inline with default error behavior.
+
+Under the hood, `'previous value'` and `'undefined value'` proxy the value. For a detailed explanation for why this is done and what a more longterm solution may be with some framework enhancements, check out the [JSDoc for the error handling strategy](https://github.com/angular-architects/ngrx-toolkit/blob/main/libs/ngrx-toolkit/src/lib/with-resource.ts#L402).
+
 ## Component Usage
 
 ```typescript

docs/docs/with-resource.md

@@ -83,6 +83,35 @@ With named resources, each resource gets prefixed properties:
 - **Single resource:** use when your store works with just one data source.
 - **Named resources:** use when your store is larger and manages multiple entities or async operations.
 
+## Error Handling
+
+Starting in NgRx Toolkit v20.6.0, error handling now has more resilient options.
+
+The behavior of Angular's resources' error handling and the NgRx SignalStore's `getState/patchState` required `withResource` to approach error handling
+with a particular strategy unique to the intersection of resources and the Signal Store.
+To prevent resource failures from blocking the store, the Toolkit provides some strategies to handle errors.
+
+```ts
+withResource(
+  () => ({
+    id: resource({
+      loader: () => Promise.resolve(1),
+      defaultValue: 0,
+    }),
+  }),
+  // Other values: 'native' and 'previous value'
+  { errorHandling: 'undefined value' }, // default if not specified
+),
+```
+
+Options:
+
+1. `'undfined value'` (default). In the event of an error, the resource's value will be `undefined`
+1. `'previous value'`. Provided the resource had a previous value, that previous value will be returned. If not, an error is thrown.
+1. `'native'`. No special handling is provided, inline with default error behavior.
+
+Under the hood, `'previous value'` and `'undefined value'` proxy the value. For a detailed explanation for why this is done and what a more longterm solution may be with some framework enhancements, check out the [JSDoc for the error handling strategy](https://github.com/angular-architects/ngrx-toolkit/blob/main/libs/ngrx-toolkit/src/lib/with-resource.ts#L402).
+
 ## Component Usage
 
 ```typescript