[Feature?]: Support for solid-js v2

[YanAnghelp]

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Summary 💡

With Solid.js 2.0 currently in beta and SolidStart 2.0 in alpha, this might be an opportune time to align both projects.

I also wonder if SolidStart will be migrated to Solid.js v2? After all, the disruptive updates in Solid.js v2 are numerous. I need to make preparations for the migration in advance.

Examples 🌈

No response

Motivation 🔦

Current state:

• Solid.js 2.0 is in beta with significant improvements to reactivity primitives and signal semantics
• SolidStart 2.0 is in alpha and actively being developed
• Both have user bases that expect instability during pre-release

Why this matters:

1. Avoid double migration: If SolidStart 2.0 stabilizes on Solid.js 1.x first, users would need to migrate twice (Start1→2, then adapting to Solid 2.0)
2. Deeper integration: Solid.js 2.0's changes to reactivity internals (owner tracking, signal semantics) could benefit SolidStart's SSR and hydration implementation
3. Ecosystem alignment: A synchronized release reduces fragmentation and provides clearer documentation paths

[lxsmnsyc]

Start 2.0 will be released before Solid 2.0, as the Solid 2.0's development story is being finalized, while Start's main goal (which is to remove vinxi) has already been defined.

Development for support for Solid 2.0 will be worked on in parallel with Start 2.0 (which will then become Start 3.0). The choice of migration is up to the user.