Add some type utils, findFeed, and fix feed listener to use limit: 0 instead of since

docs/feeds/controller.md

@@ -30,6 +30,12 @@ export class FeedController {
 
   // Load events with specified limit
   load(limit: number): Promise<void>
+
+  // Get listener function (memoized)
+  getListener(): Promise<() => Promise<void>>
+
+  // Listen for new events in the feed
+  listen(): Promise<void>
 }
 ```
 
@@ -90,4 +96,10 @@ await controller.load(50)
 
 // Load more events
 await controller.load(50)
+
+// Listen for new events
+const unlisten = controller.listen()
+
+// Unsubscribe from listener
+unlisten()
 ```

docs/feeds/utils.md

@@ -123,6 +123,23 @@ walkFeed(feed, (node) => {
 })
 ```
 
+Find a specific feed in a feed tree:
+
+```typescript
+const feed = makeIntersectionFeed(
+  makeAuthorFeed("pubkey1"),
+  makeUnionFeed(
+    makeKindFeed(1),
+    makeTagFeed("#t", "bitcoin")
+  )
+)
+
+// Find a feed matching a specific condition
+const bitcoinTagFeed = findFeed(feed, (f) =>
+  isTagFeed(f) && getFeedArgs(f)[1] === "bitcoin"
+)
+```
+
 ## Feed Simplification
 
 Flatten nested feeds of the same type:

docs/lib/tools.md

@@ -2,6 +2,36 @@
 
 The `Tools` module provides a comprehensive collection of utility functions for common programming tasks. It includes functions for array manipulation, object handling, type checking, math operations, and more.
 
+## Working with types
+
+Utility types for TypeScript development:
+
+```typescript
+// Override properties of type T with properties from type R
+export type Override<T, R> = Omit<T, keyof R> & R;
+
+// Make specific properties of type T optional
+export type MakeOptional<T, K extends keyof T> = Override<T, Partial<Pick<T, K>>>;
+```
+
+Examples:
+```typescript
+interface User {
+  id: string;
+  name: string;
+  email: string;
+  age: number;
+}
+
+// Override the id to be a number instead
+type UserWithNumericId = Override<User, { id: number }>;
+// Result: { id: number; name: string; email: string; age: number; }
+
+// Make email and age optional
+type PartialUser = MakeOptional<User, 'email' | 'age'>;
+// Result: { id: string; name: string; email?: string; age?: number; }
+```
+
 ## Basic functional programming utilities
 
 ```typescript