Wizard: offer optional 'special' reference databases (Austrian Bundesliga, Ajedrez Correspondence)

[jozef2svrcek]

Wizard: offer optional "special" reference databases

Beyond the core deep-history base (Ajedrez / BYO-Megabase, see #149), offer a small set of optional, opt-in "special" databases a user can add at wizard time (and via Maintenance → Sources). These are niche/complementary, not defaults — they shouldn't complicate the main three-option choice (#149); surface them as an optional "also add…" list.

Databases to add

1. Austrian Bundesliga

• League games (Austrian team championship). Already a long-standing candidate (Support for more reference databases #40, Server-side source-manifest service (Lumbra's, Bundesliga) — decouple fragile URL discovery from app releases #94).
• Acquisition is fragile — files are scattered across pages with no clean system (Server-side source-manifest service (Lumbra's, Bundesliga) — decouple fragile URL discovery from app releases #94). Plan: host a clean copy ourselves (TBD) rather than scrape per-client.
• Relates to Server-side source-manifest service (Lumbra's, Bundesliga) — decouple fragile URL discovery from app releases #94 (server-side manifest / hosting).

2. Ajedrez Correspondence (AJ-COR)

• Public-domain correspondence-chess database from Ajedrez Data — https://ajedrezdata.com/databases/corr/correspondence-database-aj-corr-000/
• Same distribution shape as Ajedrez OTB (numbered AJ-COR-###.7z series, direct HTTP) — so it reuses the existing Ajedrez feed driver / bulk import path with a new catalog key.
• Scale (per En Croissant's copy): ~1.5 M games, ~40k players.

Nuances to keep in mind

• Correspondence ≠ OTB player identity. Correspondence chess uses ICCF IDs/ratings, not FIDE — so the FIDE-keying / name→FIDE backfill machinery (Choose the deep-history reference source(s) for LPDO (FIDE coverage, licenses) #142) likely doesn't apply the same way (expect ~0% FIDE, like Ajedrez OTB, and ICCF as the natural key instead). Worth confirming coverage before wiring it into any FIDE-dependent flow.
• Distinct collection / provenance. Each ships into its own collection (as the multi-source design intends), so users can filter/enable independently.
• Not default-on. Keep Onboarding wizard: simplify the reference-database step to three options (none / free-managed / bring-your-own) #149's main choice to three options; these are extras a user opts into.

Work

• Catalog entries: bundesliga-at (bulk, hosted copy / manifest via Server-side source-manifest service (Lumbra's, Bundesliga) — decouple fragile URL discovery from app releases #94) and ajedrez-corr (bulk, AJ-COR series — reuses the Ajedrez driver).
• Wizard: an optional "additional/special databases" affordance (multi-select), separate from the primary base choice.
• Measure FIDE/ICCF coverage of each once available (same sources fide-coverage tooling from CLI: reference-source overlap analysis for the TWIC/Ajedrez cut-off (#142) #144).

Relates to

#40 (more reference databases), #94 (manifest/hosting for Bundesliga), #142 (source selection), #149 (wizard simplification).