feat: implement dual-pipeline signal engine service

New service at services/signal_engine/ implementing concurrent heuristic
(deterministic scoring) and probabilistic (Bayesian inference) pipelines
that evaluate technical signals across 6 timeframes (M30-M) and produce
independent BUY/WATCH/SKIP verdicts per ticker per evaluation tick.

Components:
- Input Normalizer: multi-source data assembly with sentinel fallbacks
- Signal Library: Fibonacci, MA Stack, RSI, Cup & Handle, Elliott Wave
- Multi-Timeframe Confluence Engine: weighted scoring with D/W/M anchors
- Hard Filter Engine: macro_bias, valuation, earnings proximity gating
- Heuristic Pipeline: S_total scoring with confidence-gated verdicts
- Probabilistic Pipeline: Bayesian log-odds with regime priors, entropy
  gating, EV_R calculation, and signal correlation penalty
- Exit Engine: stop-loss, targets, trailing ATR-based stops
- Delta Analyzer: pipeline agreement tracking with rolling Redis metrics
- Output Formatter: SignalOutput contract + Recommendation schema mapping
- Worker orchestrator: concurrent pipelines with failure isolation
- Main entry point: queue polling with fail-safe config loading

Infrastructure:
- Migration 039: signal_engine_outputs table with 3 indexes
- Helm chart: signalEngine service entry (processing tier)
- Redis key: QUEUE_SIGNAL_ENGINE constant

Tests: 390 tests (unit + property-based) covering all components
Config: dual_pipeline_enabled=false by default (safe rollout)

services/signal_engine/signals/rsi.py

@@ -0,0 +1,149 @@
+"""RSI (Relative Strength Index) signal evaluator.
+
+Computes the standard 14-period RSI using Wilder's smoothing method and
+produces overbought (RSI > 70 → BEARISH) or oversold (RSI < 30 → BULLISH)
+signals with strength scaled by distance from the threshold.
+
+When RSI is between 30 and 70 (neutral zone), no signal is produced.
+"""
+
+from __future__ import annotations
+
+from services.signal_engine.models import OHLCVBar, SignalDirection, SignalResult
+from services.signal_engine.signals.base import validate_lookback
+
+# Default RSI period (standard Wilder 14-period)
+DEFAULT_RSI_PERIOD: int = 14
+
+# Minimum bars required: period + 1 (for initial price change calculation)
+DEFAULT_MIN_BARS: int = DEFAULT_RSI_PERIOD + 1  # 15
+
+# Overbought / oversold thresholds
+OVERBOUGHT_THRESHOLD: float = 70.0
+OVERSOLD_THRESHOLD: float = 30.0
+
+# Maximum possible distance from threshold (used for strength scaling)
+_MAX_DISTANCE_OVERBOUGHT: float = 100.0 - OVERBOUGHT_THRESHOLD  # 30
+_MAX_DISTANCE_OVERSOLD: float = OVERSOLD_THRESHOLD - 0.0  # 30
+
+# Confidence multiplier
+_CONFIDENCE_MULTIPLIER: float = 0.85
+
+
+def compute_rsi(bars: list[OHLCVBar], period: int = DEFAULT_RSI_PERIOD) -> float | None:
+    """Compute RSI using Wilder's smoothing method.
+
+    Args:
+        bars: OHLCV bar series (oldest-first).
+        period: RSI period (default 14).
+
+    Returns:
+        RSI value in [0, 100], or ``None`` if insufficient data.
+    """
+    min_bars = period + 1
+    if len(bars) < min_bars:
+        return None
+
+    closes = [bar.close for bar in bars]
+
+    # Calculate price changes
+    changes = [closes[i] - closes[i - 1] for i in range(1, len(closes))]
+
+    # Separate gains and losses for the first `period` changes
+    first_gains = [max(0.0, c) for c in changes[:period]]
+    first_losses = [max(0.0, -c) for c in changes[:period]]
+
+    avg_gain = sum(first_gains) / period
+    avg_loss = sum(first_losses) / period
+
+    # Apply Wilder smoothing for subsequent changes
+    for c in changes[period:]:
+        gain = max(0.0, c)
+        loss = max(0.0, -c)
+        avg_gain = (avg_gain * (period - 1) + gain) / period
+        avg_loss = (avg_loss * (period - 1) + loss) / period
+
+    # Avoid division by zero: if avg_loss is 0, RSI is 100
+    if avg_loss == 0.0:
+        return 100.0
+
+    rs = avg_gain / avg_loss
+    rsi = 100.0 - (100.0 / (1.0 + rs))
+    return rsi
+
+
+class RSIEvaluator:
+    """RSI signal evaluator.
+
+    Satisfies the :class:`~services.signal_engine.signals.base.SignalEvaluator`
+    protocol.
+
+    Parameters
+    ----------
+    period:
+        RSI calculation period.  Defaults to ``14``.
+    """
+
+    def __init__(self, period: int = DEFAULT_RSI_PERIOD) -> None:
+        self.period = period
+        self.min_bars = period + 1
+
+    # ------------------------------------------------------------------
+    # Public API (SignalEvaluator protocol)
+    # ------------------------------------------------------------------
+
+    def evaluate(
+        self,
+        bars: list[OHLCVBar],
+        timeframe: str,
+    ) -> SignalResult | None:
+        """Evaluate RSI on *bars* for *timeframe*.
+
+        Returns ``None`` when there are fewer than ``period + 1`` bars
+        or when RSI is in the neutral zone (30–70).
+        """
+        if not validate_lookback(bars, self.min_bars):
+            return None
+
+        rsi = compute_rsi(bars, self.period)
+        if rsi is None:
+            return None
+
+        # Overbought: RSI > 70 → BEARISH (potential reversal down)
+        if rsi > OVERBOUGHT_THRESHOLD:
+            distance = rsi - OVERBOUGHT_THRESHOLD
+            strength = min(1.0, max(0.0, distance / _MAX_DISTANCE_OVERBOUGHT))
+            confidence = strength * _CONFIDENCE_MULTIPLIER
+            return SignalResult(
+                signal_type="rsi",
+                timeframe=timeframe,
+                strength=strength,
+                direction=SignalDirection.BEARISH,
+                confidence=confidence,
+                metadata={
+                    "rsi": rsi,
+                    "period": self.period,
+                    "zone": "overbought",
+                },
+            )
+
+        # Oversold: RSI < 30 → BULLISH (potential reversal up)
+        if rsi < OVERSOLD_THRESHOLD:
+            distance = OVERSOLD_THRESHOLD - rsi
+            strength = min(1.0, max(0.0, distance / _MAX_DISTANCE_OVERSOLD))
+            confidence = strength * _CONFIDENCE_MULTIPLIER
+            return SignalResult(
+                signal_type="rsi",
+                timeframe=timeframe,
+                strength=strength,
+                direction=SignalDirection.BULLISH,
+                confidence=confidence,
+                metadata={
+                    "rsi": rsi,
+                    "period": self.period,
+                    "zone": "oversold",
+                },
+            )
+
+        # Neutral zone (30 ≤ RSI ≤ 70): no signal
+        return None