fix(prolink): preserve payload query param

[omerbek]

Summary

Fixes #376.

• Applies additional query params before setting the required p payload parameter.
• Ensures additionalQueryParams.p cannot overwrite the encoded prolink payload.
• Adds a regression test covering the overwrite case while preserving other additional params.

Testing

corepack yarn install --immutable
# completed with existing peer dependency warnings

corepack yarn workspace @base-org/account exec vitest run src/interface/public-utilities/prolink/createProlinkUrl.test.ts
# passed, 22 tests

corepack yarn biome check packages/account-sdk/src/interface/public-utilities/prolink/createProlinkUrl.ts packages/account-sdk/src/interface/public-utilities/prolink/createProlinkUrl.test.ts
# passed

git diff --check
# passed

Note: corepack yarn workspace @base-org/account typecheck currently fails in this clean checkout because src/ui/Dialog/Dialog.tsx imports generated ./Dialog-css.js; this PR only touches the prolink utility and test.

[cb-heimdall]

🟡 Heimdall Review Status

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