DeepSeek V4-Flash news enrichment: LLM sentiment, surprise direction, summary

Three display/warning-only upgrades to the news engine, all behind the
existing keyword path as fallback — signals are never gated on LLM
output (event_risk_caps_signals / sentiment_affects_signals stay False
per the 2026-07 audit; backtester use_news=False untouched):

- Headline sentiment: one batched call per 600s cache window (capped at
  25 new headlines, sha1-cached so repeats are never re-sent) overrides
  the keyword scores per currency with the gold-inverse doctrine encoded
  in the prompt.
- Release surprises: get_event_risk_level's description now says which
  way the print pulls GOLD ("— gold bearish: strong jobs lift yields"),
  fixing the documented numeric-only gap; risk level and windows
  unchanged.
- Market summary: 1-2 sentence macro blurb on SignalReport.news_summary,
  rendered in Telegram alerts (📰) and the CLI (🧠).

New llm_client.py: requests-only OpenAI-compatible client (no SDK), one
attempt per call, UTC-day request cap, singleton so the cap survives
per-scan NewsEngine reconstruction. Config: deepseek block in
config.json + DEEPSEEK_API_KEY env; absent key = fully inert.

Live-measured API behavior baked in: V4-Flash is a hybrid thinking model
— requests send thinking:disabled (reasoning otherwise blew the timeout
and could exhaust max_tokens before the answer); prompts are static
module constants so DeepSeek's prefix cache prices repeat calls at the
cache-hit rate; scores use compact [s, xau] pairs; timeout 12s.

Tests 273 → 286 (new Module 19 + deepseek config tests).

Claude-Session: https://claude.ai/code/session_01Nsd8HcrV67GbCZXxZEn1Ma

main.py

@@ -161,6 +161,8 @@ def print_signal_report(report: SignalReport, detail: bool = False):
         print(f"  {Colors.YELLOW}📅{Colors.RESET} {report.event_description}")
     if report.news_description and report.news_description != "Neutral news sentiment":
         print(f"  {Colors.MAGENTA}📰{Colors.RESET} {report.news_description}")
+    if report.news_summary:
+        print(f"  {Colors.MAGENTA}🧠{Colors.RESET} {report.news_summary}")
 
     # ── 6. DETAIL (only with --detail) ─────────────────────────────
     if detail and report.primary_analysis:
@@ -206,6 +208,7 @@ def report_to_dict(report: SignalReport) -> dict:
         "event_description": report.event_description,
         "news_sentiment": round(report.news_sentiment, 3),
         "news_description": report.news_description,
+        "news_summary": report.news_summary,
         "bullish_reasons": report.bullish_reasons,
         "bearish_reasons": report.bearish_reasons,
         "warnings": report.warnings,