fix(solid-start): harden SSR asset manifest wiring for SSR'd lazy() components

[ryansolid]

Problem

99756c0 wired vite-plugin-solid's client-assets manifest
(virtual:solid-manifest) into the Solid SSR renderers, closing the gap where
TanStack Start never fed Vite's client asset manifest into Solid's rendering:
SSR'd lazy() components (Solid's lazy, not route-level splitting) rendered
without their chunk's CSS, without <link rel="modulepreload"> hints, and
without the serialized asset map the client needs to gate hydration of the
boundary on those chunks. Start's own manifest is route-keyed and intentionally
excludes dynamic-import chunks, so it cannot answer those per-module lookups.

Two things were still missing after that commit:

1. Test coverage for two of the three deliverables. The start-manifest
   e2e asserted the stylesheet side of the fix only. Nothing pinned the head
   modulepreload hints or the hydration asset map — a silent regression to the
   route-keyed manifest fallback (e.g. the plugin's stub swap failing to
   resolve) would keep the suite green while losing early chunk discovery and
   asset-gated hydration.
2. The pinned vite-plugin-solid (3.0.0-next.23) predates fixes to the
   exact bridge this feature consumes. 3.0.0-next.24 makes the dev asset
   resolver answer synchronously once cached (nested lazy() under
   re-created router outlets — Start's shape — could loop the SSR pass into a
   stack overflow against the always-async bridge), keeps transient dev bridge
   failures retryable instead of permanently stripping a module's assets for
   the dev session, and makes lazy-asset manifest keys survive module query
   strings and non-root Vite base paths.

Mechanism

No production code changes; the injection seam from 99756c0 is untouched
and already general:

• The only thing Start supplies is the manifest render option
  (manifest ?? clientAssetsManifest ?? router.ssr?.manifest in
  renderRouterToStream/renderRouterToString). No hint-specific logic lives
  in Start.
• Solid's renderer owns head emission: pre-shell assets splice in before the
  in-tree </head> of the user Document; post-shell assets stream as
  modulepreload / load-gated stylesheet links; arbitrary head tags ride the
  same channel. A future head-management (useHead-style) API flows through
  this seam with zero further Start changes — modulepreload hints are just its
  first consumer.

The commits:

1. Upgrade vite-plugin-solid to 3.0.0-next.24 — same monorepo-wide range
   bump convention as the beta-32 upgrade (101 package.json pins +
   lockfile). next.24 carries the bridge hardening described above.
2. Two request-level e2e tests in the existing start-manifest suite,
   using its established helpers/style, against the built app:
   • direct SSR entry to /lazy-css-lazy emits exactly one head
     modulepreload for the lazy chunk (SharedWidgetLazy-*.js) and one for
     its statically imported widget chunk, plus the chunk stylesheet — and
     routes that never render the component emit no hints for it;
   • the hydration payload serializes a boundary→chunk _assets map pointing
     at the same chunk URL the head hinted, which the client awaits before
     hydrating the boundary.
3. Upgrade vite-plugin-solid to 3.0.0-next.26 — keeps the pin current.
   next.25/next.26 are patch releases with no changes to the manifest bridge
   (custom-extensions native-compiler fix, start.env prefix guard,
   streaming backpressure fix, Fetchable SSR service entry, vitest
   browser-mode jsdom default).

The tests read only the served HTML: emitted link tags and the documented
_$HY.r["…_assets"] hydration payload shape. They touch zero Solid
internals and no Start internals — if either renderer or bridge changes how
assets are resolved, the assertions keep expressing the user-visible contract.

Verification

All against this branch rebased on solid-router-v2-pre (solid-js
2.0.0-beta.32, vite-plugin-solid 3.0.0-next.26):

• e2e/solid-start/start-manifest: 12 passed (10 pre-existing + 2 new).
• e2e/solid-start/basic: 80 passed, 4 skipped (pre-existing skips).
• e2e/solid-start/selective-ssr: 11 passed.
• Unit and type suites for @tanstack/solid-router, @tanstack/solid-start,
  @tanstack/solid-start-client, @tanstack/solid-start-server: all pass,
  no type errors.

Served HTML for a prod build of the start-manifest app, direct request to
/lazy-css-lazy — initial <head> (route-manifest hints carry _hk,
Solid-renderer hints for the SSR'd lazy() follow):

<link _hk=… rel="modulepreload" href="/assets/index-g1ZHl8-f.js" />
<link _hk=… rel="modulepreload" href="/assets/lazy-css-lazy-6_rXvEDt.js" />
<link rel="stylesheet" href="/assets/SharedWidget-BAtMnCRs.css">
<link rel="modulepreload" href="/assets/SharedWidgetLazy-JHp4Eeyx.js">
<link rel="modulepreload" href="/assets/web-DOt6yccJ.js">
<link rel="modulepreload" href="/assets/SharedWidget-cFj1aX4_.js">

and the hydration-gating map in the payload:

_$HY.r["…_assets"]=($R[3]={"…000":"/assets/SharedWidgetLazy-JHp4Eeyx.js"});

Dev mode verified manually (vite dev, same route): modulepreload for the dev
module URL (/src/components/SharedWidgetLazy.tsx), _assets map serialized,
no asset-manifest warnings in the server log.

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