New EnvVars Supercharge Shuttle's Snapchain Connectivity!

Revolutionary adjustments improve RPC efficiency with extended timeouts, paving the way for seamless data streaming.

Commit Details:

feat: add envvars to shuttle for consuming from snapchain (#2510) For subscribing to the snapchain cluster, it's useful to have a longer subscribe rpc timeout given there isn't consistent activity on the cluster and it's required to use the standard (non-streaming) bulk rpcs. This feature adds config via envvars for these parameters. ## Merge Checklist _Choose all relevant options below by adding an `x` now or at any time before submitting for review_ - [x] PR title adheres to the [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/) standard - [x] PR has a [changeset](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#35-adding-changesets) - [x] PR has been tagged with a change label(s) (i.e. documentation, feature, bugfix, or chore) - [x] PR includes [documentation](https://github.com/farcasterxyz/hub-monorepo/blob/main/CONTRIBUTING.md#32-writing-docs) if necessary. <!-- start pr-codex --> --- ## PR-Codex overview This PR focuses on adding environment variables to the `shuttle` application for configuration, particularly for streaming RPCs and timeout settings. ### Detailed summary - Introduced `USE_STREAMING_RPCS_FOR_BACKFILL` and `SUBSCRIBE_RPC_TIMEOUT` environment variables in `env.ts`. - Modified the `constructor` in `MessageReconciliation` to accept a new parameter `useStreamingRpcs`. - Updated `establishStream` method call to conditionally execute based on `useStreamingRpcs`. - Adjusted the instantiation of `MessageReconciliation` in `reconcileFids` to include `USE_STREAMING_RPCS_FOR_BACKFILL`. > ✨ Ask PR-Codex anything about this PR by commenting with `/codex {your question}` <!-- end pr-codex -->