Added time-based-sync demo entry in root README and PowerSync CLI install note in demo's README

Author: bean1352

README.md

@@ -73,6 +73,7 @@ Demo applications are located in the [`demos/`](./demos/) directory. Also see ou
 
 - [demos/react-supabase-todolist](./demos/react-supabase-todolist/README.md): A React to-do list example app using the PowerSync Web SDK and a Supabase backend.
 - [demos/react-supabase-todolist-tanstackdb](./demos/react-supabase-todolist-tanstackdb/README.md): A React to-do list example app using the PowerSync Web SDK and a Supabase backend + [TanStackDB](https://tanstack.com/db/latest) collections.
+- [demos/react-supabase-time-based-sync](./demos/react-supabase-time-based-sync/README.md): A React demo using Sync Streams to subscribe to date-filtered data dynamically, with a Supabase backend.
 - [demos/react-multi-client](./demos/react-multi-client/README.md): A React widget that illustrates how data flows from one PowerSync client to another.
 - [demos/yjs-react-supabase-text-collab](./demos/yjs-react-supabase-text-collab/README.md): A React real-time text editing collaboration example app powered by [Yjs](https://github.com/yjs/yjs) CRDTs and [Tiptap](https://tiptap.dev/), using the PowerSync Web SDK and a Supabase backend.
 - [demos/vue-supabase-todolist](./demos/vue-supabase-todolist/README.md): A Vue to-do list example app using the PowerSync Web SDK and a Supabase backend.

demos/react-supabase-time-based-sync/README.md

@@ -1,6 +1,6 @@
 # PowerSync + Supabase: Time-Based Sync (Local-First)
 
-This demo shows how to use [PowerSync Sync Streams](https://docs.powersync.com/sync/sync-streams) to dynamically control which data is synced to the client. The backend contains a set of issues with `created_at` / `updated_at` as **`TIMESTAMPTZ`** in Postgres. Each selected date creates its own sync stream subscription with a `date` parameter. Toggling dates on or off adds or removes stream subscriptions and PowerSync syncs the matching issues. TTL is set to 0 so data is removed immediately when dates are deselected.
+This demo shows how to use [PowerSync Sync Streams](https://docs.powersync.com/sync/sync-streams) to dynamically control which data is synced to the client based on a date. The backend contains a set of issues with `created_at` / `updated_at` as **`TIMESTAMPTZ`** in Postgres. Each selected date creates its own sync stream subscription with a `date` parameter. Toggling dates on or off adds or removes stream subscriptions and PowerSync syncs the matching issues. TTL is set to 0 so data is removed immediately when dates are deselected.
 
 This lets you model patterns like “sync the last N days of data” or “sync only the time ranges the user cares about” without re-deploying sync rules.
 
@@ -68,6 +68,8 @@ The demo runs against local Supabase (`supabase start`) and self-hosted PowerSyn
 
 4. Start local Supabase + local PowerSync:
 
+   > Ensure the [PowerSync CLI](https://docs.powersync.com/tools/cli) is installed before running the following command.
+
    ```bash
    pnpm local:up
    ```