[Feature] Introduce Native Static Site Generation (SSG) via 'gutter export' CLI

[HaHiepThanh]

📋 Context & Problem Description

Gutter CLI currently supports hot SSR (dynamic compilation/execution) and CSR. However, for content-centric pages like blogs, documentations, and landing pages, dynamic SSR adds unnecessary CPU overhead on the server. Developers currently have to write custom scripts to crawl and export HTML files.

💡 Proposed Solution & Implementation Plan

Add an SSG command to Gutter CLI:

gutter export

Implementation Steps:

1. Route Declaration: Introduce a configuration option in gutter.Config or a CLI config file to list static routes to export (e.g. []string{"/", "/about", "/blog"}).
2. Crawler/Render Walk: When gutter export runs, build the host app and invoke RenderToHTML for each route.
3. Export Directory Structure: Save the returned HTML to corresponding paths in the ./dist directory (e.g. / -> dist/index.html, /about -> dist/about/index.html).
4. Asset Bundle: Copy all WASM and static assets into the export directory.

🎯 Impact & Benefits

• Serverless Deployments: Enables Gutter apps to be deployed directly to static hosts like Cloudflare Pages, Vercel, Netlify, and GitHub Pages.
• Instant TTFB: Zero server-side rendering latency at request time.

🏷️ Suggested Labels

feature, cli, ssr