fix: Prodia language models silently ignore seed settings (#19487)

## Background

Prodia language models silently discarded the standard seed setting,
unlike other unsupported call settings that emitted warnings.

## Root Cause

ProdiaLanguageModel.doGenerate omitted options.seed from its
unsupported-setting checks while also excluding it from the request
config; the failing replay confirmed both generateText and streamText
lacked the warning, with doStream reusing doGenerate warnings.

## Summary

Added an unsupported seed warning, regression coverage, and a patch
changeset for @ai-sdk/prodia.

## Testing

Extended the existing unsupported-language-model-settings test to
provide seed and assert its warning; validated both generation and
streaming through the recorded replay.

## End-to-end Validation

- `pnpm -C examples/ai-functions exec tsx
src/reproduction/prodia-seed-warning-issue-17938.ts` — exited
successfully and confirmed both generateText and streamText warn about
seed.
- `pnpm -C examples/ai-functions exec tsx -e "<live Prodia generateText
call>"` — live request returned one file and warnings for topK, seed,
and toolChoice.

## Related Issues

Fixes #17938

Closes #19485

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Co-authored-by: ai-sdk-factory <308175966+ai-sdk-factory@users.noreply.github.com>
Co-authored-by: Gregor Martynus <39992+gr2m@users.noreply.github.com>
Co-authored-by: reizam <12397287+reizam@users.noreply.github.com>