Pin the webapp and API at the Robinhood metaboard registry (#2895)

## Summary

- Pin the v6 webapp and the API crate at rain.strategies `1245226`, the head of #137.
- That registry commit points settings and every strategy at `784e501`, which adds `metaboards.robinhood`.

## Test plan

- [x] Merge rainlanguage/rain.strategies#137 with a merge commit so `1245226` stays reachable
- [ ] Confirm the pinned registry URL returns the Robinhood metaboard line
- [ ] Deploy a Robinhood order on v6 and confirm `Key 'robinhood' not found` is gone

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **Updates**
  - The default registry now points to a newer snapshot in both the web app and API.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: Siddharth2207

crates/rest_api/src/config.rs

@@ -1,6 +1,6 @@
 use std::path::PathBuf;
 
-pub const DEFAULT_REGISTRY_URL: &str = "https://raw.githubusercontent.com/rainlanguage/rain.strategies/73327c8e874d16de05c0849c60c281ecb529dbb1/registry";
+pub const DEFAULT_REGISTRY_URL: &str = "https://raw.githubusercontent.com/rainlanguage/rain.strategies/cb916e1a5bfcc0aead36d183de08b85ddfe21979/registry";
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct Config {

packages/webapp/src/lib/constants.ts

@@ -1,2 +1,2 @@
 export const REGISTRY_URL =
-  "https://raw.githubusercontent.com/rainlanguage/rain.strategies/73327c8e874d16de05c0849c60c281ecb529dbb1/registry";
+  "https://raw.githubusercontent.com/rainlanguage/rain.strategies/cb916e1a5bfcc0aead36d183de08b85ddfe21979/registry";