feat: Support display custome certificate provider

[Hoshino-Yumetsuki]

Solve #4612

Greptile Summary

Adds certificate-resolver discovery and display for domain configuration.

• Reads resolver names from local or remote Traefik static configuration.
• Exposes discovered resolvers through the domain API with organization ownership checks.
• Presents discovered resolvers as selectable certificate providers while preserving the existing custom-resolver representation.

Confidence Score: 4/5

The PR appears safe to merge, though resolver-discovery failures should be surfaced instead of silently presenting an empty provider list.

The resolver mapping and server authorization paths are coherent, with the remaining non-blocking concern limited to lost diagnostics and misleading empty results when remote configuration retrieval or parsing fails.

Files Needing Attention: packages/server/src/utils/traefik/web-server.ts

_{Reviews (1): Last reviewed commit: "Merge branch 'Dokploy:canary' into canar..." | Re-trigger Greptile}

Greptile also left 1 inline comment on this PR.

[greptile-apps]

Resolver discovery errors are hidden

The catch-all converts SSH, file-access, and YAML-parsing errors into an empty resolver list, making configured providers disappear from the selector without giving users or operators any diagnostic that discovery failed.