KOL feeds: fix dead/blocked sources, drop stale feeds (29→25)

Feed-health pass over KOL_FEEDS:
- raoulpal: stale Substack (last 2024-05) → Real Vision podcast feed
- dampedspring: paywalled (0 entries) → free "Damped Spring 101" Substack
- unchained: Cloudflare 403 → canonical Megaphone podcast feed
- lynalden: Cloudflare 202 → FeedBurner mirror
- glassnode: recovered via httpx http2=True (was 403 on HTTP/1.1)
- browser User-Agent + Accept headers on feed fetch
- removed dead feeds with no active replacement: placeholder,
  dragonfly, niccarter, eugene
- pin h2==4.3.0 (required by http2=True)

All 25 remaining feeds verified fetching real body content; newest
post per feed ≤88d. Bundles in-flight KOL-module work already in the
working tree (kol_x ingest, migration 027, tests).

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

app/services/circuit_breaker.py

@@ -129,7 +129,7 @@ async def check_and_trip(
 
     today_trades = await _trades_for_system(db, wallet, start_of_day, system)
     today_pnl = sum(t.pnl_usd or 0 for t in today_trades)
-    dd_limit = -CB_DAILY_DD_USD_PER_BASE * sub.position_size_usd * 10
+    dd_limit = -CB_DAILY_DD_USD_PER_BASE * sub.position_size_usd
     if today_pnl < dd_limit:
         reason = "daily_dd"
         logger.warning("CB[%s] trip [daily_dd] %s: pnl=%.2f < %.2f",