fix(signals): align store overloads

[GabbeV]

Summary

Align store overloads across @solidjs/signals and the solid-js client/server entry points.

• Standardize plain forms as (initialValue, options?) and derived forms as (fn, seed, options?).
• Move shallow to StoreOptions; keep projection-only fields on ProjectionOptions.
• Expose the existing options argument on plain optimistic stores.
• Type derived optimistic stores as Refreshable<Store<T>>.
• Align async-iterable support and option types across entry points.
• Add focused type coverage and a changeset.

Depends on #3258 and should be rebased onto next after it merges.

Validation

• pnpm types (packages/signals)
• pnpm test-types and pnpm types (packages/solid)
• Shallow-store and optimistic-store focused tests

[changeset-bot]

🦋 Changeset detected

Latest commit: f45a213

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@solidjs/signals	Patch
solid-js	Patch
test-integration	Patch
@solidjs/web	Patch
@solidjs/element	Patch
@solidjs/h	Patch
@solidjs/html	Patch
@solidjs/universal	Patch
@solidjs/babel-plugin	Patch
@solidjs/compiler	Patch
@solidjs/diagnostics	Patch

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[codspeed-hq]

Merging this PR will degrade performance by 32.71%

❌ 1 regressed benchmark
✅ 135 untouched benchmarks

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Benchmark	BASE	HEAD	Efficiency
❌	merge	187.9 µs	279.2 µs	-32.71%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing GabbeV:fix/align-store-overloads (f45a213) with next (ff96a67)}