feat(species): derived verified reference links (GBIF/Wikipedia/Wikispecies)

Add a read-only "Learn more" section on the variety detail that surfaces
verified external references for the linked species, built deterministically
from bundled identifiers — no titles bundled, no network, offline-first:

- GBIF taxon page from the backbone key
- Wikipedia via Wikidata Special:GoToLinkedPage (locale-aware, RTL-safe,
  falls back to the Wikidata item when a language lacks the article)
- Wikispecies from the scientific name

Enrich the bundled catalog (species.json v3) with gbif_key + wikidata_qid for
all 14 species, cross-checked (each QID carries GBIF ID P846 = the key).
Schema already had the columns; seedBundled now persists and backfills them.

The grower's own manual links stay but are demoted (progressive disclosure):
the section only shows when links exist and "Add link" is a low-emphasis
button, since hand-adding a link is the rarer power move.

Pure-Dart link builder is unit-tested; repo persistence/backfill and the
detail-screen section are covered too.

apps/app_seeds/lib/i18n/en.i18n.json

@@ -148,6 +148,10 @@
     "addLink": "Add link",
     "linkUrl": "URL",
     "linkTitle": "Title (optional)",
+    "reference": "Learn more",
+    "refGbif": "GBIF",
+    "refWikipedia": "Wikipedia",
+    "refWikispecies": "Wikispecies",
     "notes": "Notes",
     "addLot": "Add lot",
     "editLot": "Edit lot",