feat: add `@aeorank/solid-start` framework plugin

[vinpatel]

SolidStart is the Solid.js meta-framework and has picked up real adoption. It's conceptually similar to SvelteKit/Nuxt (file-based routing, SSR) so the plugin shape should mirror packages/sveltekit almost 1:1.

Scope

Ship packages/solid-start as @aeorank/solid-start:

• A Vite plugin or SolidStart config helper that wires @aeorank/core generators into the build pipeline
• Writes the 9 AEO files to the SolidStart output directory

Reference

• packages/sveltekit is the closest shape — copy its Vite plugin setup
• Generators live in packages/core/src/generators/

Acceptance

• packages/solid-start/ publishes as @aeorank/solid-start
• Tests verify 9 files are generated into the build output
• Docs page at apps/docs/.../frameworks/solid-start/