0.8.1

Implement list issuers (#25)

* feat(api): add GET /issuer endpoint for paginated listing of issuer DIDs

Extends the OpenAPI spec with a new GET /issuer endpoint that returns
a paginated list of all trusted issuer DIDs. Adds PageSize and Page
query parameters and a TrustedIssuersListResponse schema.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat(api): implement GET /issuer endpoint for paginated listing of DIDs

Adds the getIssuers method to TrustedIssuersListController that returns
a paginated, sorted list of all trusted issuer DIDs. Includes tests for
default pagination, custom page size, second page, empty results, and
invalid page size rejection.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: claude <claude@gitea.com>