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/sidebars.ts

@@ -1,33 +1,15 @@
-import type {SidebarsConfig} from '@docusaurus/plugin-content-docs';
+import type { SidebarsConfig } from "@docusaurus/plugin-content-docs"
 
 // This runs in Node.js - Don't use client-side code here (browser APIs, JSX...)
 
-/**
- * Creating a sidebar enables you to:
- - create an ordered group of docs
- - render a sidebar for each doc of that group
- - provide next/previous navigation
-
- The sidebars can be generated from the filesystem, or explicitly defined here.
-
- Create as many sidebars as you want.
- */
 const sidebars: SidebarsConfig = {
-  // By default, Docusaurus generates a sidebar from the docs folder structure
-  tutorialSidebar: [{type: 'autogenerated', dirName: '.'}],
-
-  // But you can create a sidebar manually
-  /*
-  tutorialSidebar: [
-    'intro',
-    'hello',
-    {
-      type: 'category',
-      label: 'Tutorial',
-      items: ['tutorial-basics/create-a-document'],
-    },
+  docsSidebar: [
+    "getting-started",
+    "state-management",
+    "query",
+    "mutation",
+    "forms",
   ],
-   */
-};
+}
 
-export default sidebars;
+export default sidebars