Per-member GW2 API key linking for character-level sync

[avandenberghe]

Summary

Split out of #9 (originally scoped as "roster + characters" sync, mirroring bbguildwow's model — but GW2's API doesn't support that model, see below).

/v2/characters is strictly scoped to the API key owner's own account (confirmed against current API docs, 2026-09-21) — there is no way to look up another player's characters by name the way WoW's Battle.net API allows via a single guild/application-level key. Class, race, and level for a GW2 character can only be synced automatically if that specific member has linked their own personal API key.

Scope

• UCP flow: a member links their own GW2 API key (scoped to account, characters) to their linked bbguild character(s).
• Per-character sync handler that, for members who've linked a key, pulls their character's profession/race/level from /v2/characters/{name}.
• Members who haven't linked a key keep manually-entered class/race/level, same as any non-API game — this is additive, not a requirement for Implement GW2 API v2 guild roster sync (name/rank/join date only) #9's roster sync to work.
• Needs its own opt-in/consent UX (a personal API key is more sensitive than a guild-leader key) and a way to handle a member revoking/rotating their key.

Related

• Implement GW2 API v2 guild roster sync (name/rank/join date only) #9 — guild roster sync (name/rank/join date), buildable today with just a guild-leader key, does not depend on this
• bbguildwow's character_sync (bbguild#361/#362) is the nearest prior art, but isn't a direct model — WoW's per-character lookup doesn't require the character's own owner to have linked anything