Add Effect v4 support, Fast Refresh tooling, and revamped docs (#56)

## Summary

- Add `effect-fc-next`, a React 19 integration targeting Effect v4 beta.
- Introduce component lifecycles, scoped resources, queries, mutations, forms, lenses, views, and refreshable components.
- Add `@effect-view/vite-plugin` for Vite Fast Refresh support.
- Add an Effect v4 example application covering the new APIs.
- Expand test coverage for both the existing and next-generation packages.
- Replace the starter Docusaurus content with complete Effect View documentation while preserving the Effect v3 docs as a versioned snapshot.
- Update the landing page, navigation, package scripts, and build output.
- Extend CI with linting, tests, package builds, Docker builds, and container publishing.

## Validation

- `bun lint:tsc`
- `bun lint:biome`
- `bun test`
- `bun run build`
- `bun pack`
- Docker image build

---------

Co-authored-by: Julien Valverdé <julien.valverde@mailo.com>
Reviewed-on: Thilawyn/effect-fc#56

packages/docs/README.md

@@ -1,41 +1,17 @@
-# Website
+# effect-fc Docs
 
-This website is built using [Docusaurus](https://docusaurus.io/), a modern static website generator.
-
-## Installation
-
-```bash
-yarn
-```
+The documentation site is built with Docusaurus.
 
 ## Local Development
 
 ```bash
-yarn start
+bun run --cwd packages/docs start
 ```
 
-This command starts a local development server and opens up a browser window. Most changes are reflected live without having to restart the server.
-
 ## Build
 
 ```bash
-yarn build
+bun run --cwd packages/docs build
 ```
 
-This command generates static content into the `build` directory and can be served using any static contents hosting service.
-
-## Deployment
-
-Using SSH:
-
-```bash
-USE_SSH=true yarn deploy
-```
-
-Not using SSH:
-
-```bash
-GIT_USER=<Your GitHub username> yarn deploy
-```
-
-If you are using GitHub pages for hosting, this command is a convenient way to build the website and push to the `gh-pages` branch.
+The static site is written to `packages/docs/build`.