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.

Claude-Session: https://claude.ai/code/session_01VPNF37MP9Kuv62B1VBrZ1b

test_all.py

@@ -1879,6 +1879,7 @@ def _():
             primary_timeframe=tf,
             confirmation_timeframes=ctfs,
         )
+        app_config.apply_pair_overrides(inline_cfg)
         if tf == Timeframe.M15:
             # Documented per-TF overrides (see xauusd.py docstring):
             # 1R minimum targets + mixed-"trending"-regime block +
@@ -2677,6 +2678,53 @@ def _():
             pass
 
 
+@test("app_config: apply_pair_overrides stamps both blocked-hours mirrors")
+def _():
+    app = AppConfig(pair_overrides={XAUUSD: {"blocked_hours_utc": [3, 4]}},
+                    scan_pairs=[XAUUSD],
+                    scan_timeframes=[Timeframe.M15])
+    cfg = apply_pair_overrides(PlatformConfig(), app)
+    assert cfg.xau_strategy.blocked_hours_utc == [3, 4]
+    assert cfg.backtest.blocked_hours_utc == [3, 4]
+    assert cfg.scan_timeframes == [Timeframe.M15]
+    # the two mirrors must be independent lists, not aliases
+    cfg.xau_strategy.blocked_hours_utc.append(5)
+    assert cfg.backtest.blocked_hours_utc == [3, 4]
+
+
+@test("app_config: M5 factory appends hour 9 on top of a JSON base")
+def _():
+    from pair_signals import PAIR_PRODUCERS
+    app = AppConfig(pair_overrides={XAUUSD: {"blocked_hours_utc": [3, 4]}},
+                    provider_settings={"twelve_data": {"api_key": "test-key"}})
+    set_app_config(app)
+    try:
+        cfg = PAIR_PRODUCERS[XAUUSD](Timeframe.M5, None)
+    finally:
+        set_app_config(_TEST_APP)
+    assert cfg.xau_strategy.blocked_hours_utc == [3, 4, 9], \
+        "validated M5 hour-9 delta must land on top of the JSON base"
+    assert cfg.backtest.blocked_hours_utc == [3, 4], \
+        "mirror carries the base only (per-TF delta is XAU-strategy-side)"
+
+
+@test("app_config: config.json.example is valid and behavior-neutral")
+def _():
+    import dataclasses
+    from pair_signals import PAIR_PRODUCERS
+    example = load_app_config(
+        os.path.join(os.path.dirname(__file__), "config.json.example"))
+    for tf in (Timeframe.M5, Timeframe.M15, Timeframe.H1, Timeframe.H4):
+        baseline = PAIR_PRODUCERS[XAUUSD](tf, None)   # under _TEST_APP
+        set_app_config(example)
+        try:
+            with_example = PAIR_PRODUCERS[XAUUSD](tf, None)
+        finally:
+            set_app_config(_TEST_APP)
+        assert dataclasses.asdict(baseline) == dataclasses.asdict(with_example), \
+            f"example config.json must be byte-identical to defaults on {tf}"
+
+
 # ══════════════════════════════════════════════════════════════════════
 #  SUMMARY
 # ══════════════════════════════════════════════════════════════════════