fix(signals): remove unsupported single-argument createEffect

[Monkeylordz]

Summary

The single-argument createEffect overload was marked deprecated for migration purposes, but in reality it just leads to hidden runtime errors.

• remove the unsupported single-argument createEffect(compute) overload so TypeScript rejects the call
• remove the development-only MISSING_EFFECT_FN guard and diagnostic
• update type coverage, diagnostic documentation, and changesets

Testing

• pnpm --dir packages/signals exec vitest run tests/createEffect.test.ts tests/diagnostics.test.ts (44 tests passed)
• pnpm --dir packages/solid test-types

[changeset-bot]

⚠️ No Changeset found

Latest commit: 75a22b3

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes changesets to release 11 packages

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

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