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).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Nsd8HcrV67GbCZXxZEn1Ma

app_config.py

@@ -85,11 +85,15 @@ _VALID_LOG_LEVELS = ("DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL")
 # AUTOSCAN_CONFIRMATIONS entries in telegram_bot.py).
 _SCANNABLE_TFS = ("M5", "M15", "H1", "H4")
 
-_KNOWN_TOP = {"telegram", "data_providers", "scanning", "pairs", "log_level", "oanda"}
+_KNOWN_TOP = {"telegram", "data_providers", "scanning", "pairs", "log_level",
+              "oanda", "deepseek"}
 _KNOWN_OANDA = {
     "account_id", "api_token", "base_url", "lot_size",
     "quality_gate", "max_hold_bars",
 }
+_KNOWN_DEEPSEEK = {
+    "api_key", "model", "enabled", "timeout_seconds", "daily_request_cap",
+}
 _KNOWN_TELEGRAM = {"token", "chat_id", "channel_id", "alert_min_quality"}
 _KNOWN_SCANNING = {"pairs", "timeframes"}
 _KNOWN_PAIR_KEYS = {"blocked_hours_utc"}
@@ -113,6 +117,7 @@ class AppConfig:
         Timeframe.M5, Timeframe.M15, Timeframe.H1, Timeframe.H4])
     pair_overrides: Dict[str, Dict[str, Any]] = field(default_factory=dict)
     oanda_settings: Dict[str, Any] = field(default_factory=dict)
+    deepseek_settings: Dict[str, Any] = field(default_factory=dict)
     log_level: str = "INFO"
 
 
@@ -248,6 +253,29 @@ def load_app_config(path: str = CONFIG_PATH) -> AppConfig:
                 "config.json: oanda.max_hold_bars must be a positive integer")
     app.oanda_settings = dict(oanda)
 
+    deepseek = raw.get("deepseek", {})
+    _check_keys(deepseek, _KNOWN_DEEPSEEK, '"deepseek"')
+    if "enabled" in deepseek and not isinstance(deepseek["enabled"], bool):
+        raise AppConfigError(
+            "config.json: deepseek.enabled must be true or false")
+    if "timeout_seconds" in deepseek:
+        ts = deepseek["timeout_seconds"]
+        if isinstance(ts, bool) or not isinstance(ts, (int, float)) or ts <= 0:
+            raise AppConfigError(
+                "config.json: deepseek.timeout_seconds must be a positive "
+                "number")
+    if "daily_request_cap" in deepseek:
+        cap = deepseek["daily_request_cap"]
+        if isinstance(cap, bool) or not isinstance(cap, int) or cap < 1:
+            raise AppConfigError(
+                "config.json: deepseek.daily_request_cap must be a positive "
+                "integer")
+    if "model" in deepseek:
+        if not isinstance(deepseek["model"], str) or not deepseek["model"]:
+            raise AppConfigError(
+                "config.json: deepseek.model must be a non-empty string")
+    app.deepseek_settings = dict(deepseek)
+
     level = raw.get("log_level", app.log_level)
     if level not in _VALID_LOG_LEVELS:
         raise AppConfigError(
@@ -339,6 +367,14 @@ def oanda_base_url(app: Optional[AppConfig] = None) -> str:
         app.oanda_settings.get("base_url", "https://api-fxpractice.oanda.com"))
 
 
+# ── DeepSeek resolution helper (env → config.json → "") ──────────────
+
+def deepseek_api_key(app: Optional[AppConfig] = None) -> str:
+    app = app or get_app_config()
+    return os.environ.get("DEEPSEEK_API_KEY") or str(
+        app.deepseek_settings.get("api_key", ""))
+
+
 # ── PlatformConfig overlay ────────────────────────────────────────────
 
 def apply_pair_overrides(