feat: company names for tickers (Alpaca backfill + subtle display)

Store an optional company name on Ticker (migration 014) and backfill it from
Alpaca's asset list in a single Trading-API call for the whole universe — no
per-ticker fetch. Runs automatically at the end of universe bootstrap and via a
manual "Backfill Names" button (admin) / POST /admin/tickers/backfill-names.

The name ships on /tickers; a shared symbol→name map (useTickerNames) lets any view
show it without its own request. Displayed subtly next to the symbol — in the global
search, the ticker header, and as a small muted line under the symbol in Top Setups
and Open Trades (no extra column, truncated so it never widens the table).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/routers/admin.py

@@ -315,6 +315,16 @@ async def bootstrap_tickers(
     return APIEnvelope(status="success", data=result)
 
 
+@router.post("/admin/tickers/backfill-names", response_model=APIEnvelope)
+async def backfill_ticker_names(
+    _admin: User = Depends(require_admin),
+    db: AsyncSession = Depends(get_db),
+):
+    """Fill in company names for tracked tickers (one Alpaca call)."""
+    result = await ticker_universe_service.backfill_ticker_names(db)
+    return APIEnvelope(status="success", data=result)
+
+
 # ---------------------------------------------------------------------------
 # Data cleanup
 # ---------------------------------------------------------------------------