feat(card-search): add a dedicated tokens category

[Go2Engle]

Summary

Add a dedicated Tokens category alongside Search cards, Browse sets, and Commander precons in Find a card. Users can browse paper token artwork directly, filter by token name and optional token set code, and add their chosen printings to the sheet.

Type of change

• Feature
• Bug fix
• Refactor
• Documentation
• Infrastructure/CI

Technical details

• Open the token gallery with the newest paper printings and support release date, name, set/collector number, color, and artist sorting in either direction.
• Request token-only Scryfall results with all printings and variations; preserve server ordering during pagination and reuse the existing one-day cache and request throttling.
• Share printing-search response handling with set browsing, treat unmatched first-page searches as empty results, and retain retryable service and pagination errors.
• Reuse card addition and preview controls to preserve selected artwork, distinct printings, repeated-copy quantities, double-faced token artwork, and the 500-card project limit.
• Guard asynchronous gallery updates when filters, sorting, or the active category change.
• Update the feature reference, print workflow guide, README feature summary and numbered workflow, and add a current token-browser screenshot.

Testing performed

All 147 application tests and 17 website tests passed. The production app build and offline website build passed.

npm ci
npm test
npm run build
npm ci --prefix site
npm test --prefix site
npm run build --prefix site -- --offline
git diff --check

• Automated coverage verifies token query scoping and escaping, optional set filters, distinct artwork, pagination ordering, double-faced tokens, missing artwork, empty results, and service failures.
• Live browser checks verified the default token gallery, both Treasure printings in TMH2, changing sort direction, unmatched-search feedback, and adding one printing twice while keeping the other printing separate.
• Reviewed desktop and 390 px mobile layouts; neither the page nor dialog had horizontal overflow.

Breaking changes

None.

Checklist

• The PR title follows Conventional Commits.
• I ran npm test and npm run build.
• I added or updated tests for behavior changes.
• I updated documentation for user-facing changes.
• I updated the README feature summary if this feature belongs on the website overview.
• I did not manually edit release versions or CHANGELOG.md.