Epic: Public JSON feeds for community FAQ and citations

[neuromechanist]

Summary

Expose two already-populated community datasets as public, read-only JSON feeds that communities can build their own frontends on. Both pipelines (FAQ generation from mailing lists/Discourse, citation tracking of canonical papers) already run on a community cron and have substantial data on dev (eeglab: 1,990 FAQ entries, 1,961 papers). Today the data is reachable only through agent tools; this epic gives it a public face.

Opt-in is per-community via a new top-level public_feeds config block:

public_feeds:
  faq: true
  citations: true

Phases

1. FAQ JSON endpoint — privacy/quality spot-check of existing faq_entries, public_feeds.faq config gate, read-only GET /{community_id}/faq over search_faq_entries exposing only safe fields, tests on real dev data.
2. Citation dashboard endpoint — add cites_doi linkage column to papers and persist it in sync_citing_papers, full citation re-sync to backfill, public_feeds.citations config gate, GET /{community_id}/citations returning per-year counts plus stacked-by-canonical-paper breakdown, tests on real dev data.

Notes

• Both feeds are read-only and config-gated; off by default.
• FAQ source content carries author names/emails, so a privacy review precedes exposure.
• Citation re-sync is cheap and re-runs on the existing schedule once the schema field is added.

[neuromechanist]

Completed via #324 (FAQ feed) and #330 (citations dashboard), merged to develop in #331.