Wire config.json overlay into the pair factory (before per-TF deltas)

Implements Task 2: apply_pair_overrides in xauusd.make_config before
the validated per-TF deltas, so e.g. M5 hour-9 appends on top of the
JSON base. Updated Module 9 equivalence test and added three parity pins.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VPNF37MP9Kuv62B1VBrZ1b

pair_signals/xauusd.py

@@ -69,6 +69,7 @@ M5-only, same per-timeframe pattern as the M15 overrides.
 
 from typing import Optional, List
 from config import PlatformConfig, Timeframe
+from app_config import apply_pair_overrides
 
 _CONFIRMATIONS = {
     Timeframe.M5:  [Timeframe.M15, Timeframe.H1],
@@ -83,6 +84,9 @@ def make_config(
     confirmation_tfs: Optional[List[Timeframe]] = None,
 ) -> PlatformConfig:
     config = PlatformConfig()
+    # Deployment overlay (config.json) BEFORE the validated per-TF
+    # deltas below, so e.g. the M5 hour-9 append lands on the JSON base.
+    apply_pair_overrides(config)
     config.primary_timeframe = primary_tf
     config.confirmation_timeframes = (
         confirmation_tfs or _CONFIRMATIONS.get(primary_tf, [Timeframe.M15, Timeframe.H4])