refactor: use the SDK recommendation client

[TaprootFreak]

Consumer side of step 2 of DFXswiss/packages#198: use the recommendation client from
@dfx.swiss/react and drop the local copies.

Depends on DFXswiss/packages#200.

Changes

• src/dto/recommendation.dto.ts and src/hooks/recommendation.hook.ts are gone; the types and
  useRecommendation now come from the package.
• confirmRecommendation / rejectRecommendation take the id instead of the whole recommendation —
  the id was the only part that ever reached the wire.

Before this can go green

The package pin in package.json still points at the published @dfx.swiss/react, which does not
export useRecommendation yet. CI stays red until DFXswiss/packages#200 is merged and published
and the pin is raised here. Verified locally against a build of that branch: tsc clean,
npm run lint clean, full suite at 673 passing with no new failures (the two suites failing on
develop today still fail, unchanged).

Note for whoever picks this up: the package types expirationDate as optional, because the API omits
it for mail invitations. The local copy declared it required. Any code that formats that date
unconditionally was rendering an invalid date for exactly that case.

[github-actions]

🤖 PR Review Bot

❌ TypeScript: 8 errors

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