Add search-then-download workflow for patch CLI

- Update api-client.ts with new search interfaces (PatchSearchResult, SearchResponse)
- Rename methods to searchPatchesByCVE, searchPatchesByGHSA, searchPatchesByPackage
- Update download.ts to implement two-phase workflow:
  - First search for patches by identifier (UUID, CVE, GHSA, or package)
  - Display search results with tier labels
  - Filter based on canAccessPaidPatches flag
  - Prompt user for confirmation when multiple patches found
  - Fetch full patch details via view endpoint for each selected patch
- Add --yes/-y flag to skip confirmation prompt

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Co-Authored-By: Claude <[email protected]>

Author: mikolalysenko