fix: smart routing in Browse — enrichment filters use /api/enriched, discovery uses /api/domains

Root cause: loadDomains() always hit /api/domains (DuckDB 72M rows) and filtered
niche/site_type/prescreen_status client-side on a random page of 100 domains —
virtually none had been classified, so Live+Beauty+Ecommerce always returned 0.

- loadDomains() now routes to /api/enriched when any enrichment filter is active
  (prescreen_status, niche, site_type, country) — all filters are server-side SQLite
- Falls back to /api/domains only when no enrichment filters are set (discovery mode)
- alpha_only and no_sld supported in both modes:
  - DuckDB: existing regex support
  - SQLite: LIKE patterns (no hyphens/digits) + dot-count (no SLD)
- Add alpha_only/no_sld params to /api/enriched endpoint and get_enriched()
- Fix stale d.classified reference in prescreenOne toast

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/beauty_main.py

@@ -155,6 +155,8 @@ async def enriched(
     site_type: str = Query(None),
     keyword: str = Query(None),
     tld: str = Query(None),
+    alpha_only: bool = Query(False),
+    no_sld: bool = Query(False),
     page: int = Query(1, ge=1),
     limit: int = Query(100, ge=1, le=1000),
 ):
@@ -162,6 +164,7 @@ async def enriched(
         min_score=min_score, country=country,
         prescreen_status=prescreen_status, niche=niche, site_type=site_type,
         keyword=keyword, tld=tld,
+        alpha_only=alpha_only, no_sld=no_sld,
         page=page, limit=limit,
     )
     return {"page": page, "limit": limit, "total": total, "results": rows}