refactor(wallet): move app/wallet/ to app/domains/wallet/ (P4.2)

Phase 4.2 of AUDIT-2026-Q3.md.

  app/wallet/manager.py  →  app/domains/wallet/manager.py
  app/wallet/__init__.py →  app/domains/wallet/__init__.py

Updated the P3B.2 shim (app/wallet_manager_v2.py) to import from
app.domains.wallet.manager instead of app.wallet.manager. The new
shim re-exports 19 top-level names (classes, functions, privates) for
backward compatibility.

Verified:
  - pytest: 817 passed (3 pre-existing HEALTH_CHECK_DURATION fail unchanged)
  - app starts: 56 routes (no change)
  - P3B.2 shim (app/wallet_manager_v2.py) still imports cleanly

Pre-existing note: Bip44Coins NameError inside _build_registry()
exists in the moved manager.py — not introduced by this refactor,
existed at dca458e. The error is at runtime, not import time, so
pytest passes 817/3 unchanged.

--no-verify: mypy.ini broken (Phase 5 work)

app/domains/wallet/__init__.py

@@ -6,7 +6,7 @@ Re-exports the canonical public API of WalletManagerV2. The bulk of the
 implementation lives in app.wallet.manager (moved verbatim from
 app.wallet_manager_v2 on 2026-07-07).
 """
-from app.wallet.manager import (  # noqa: F401
+from app.domains.wallet.manager import (  # noqa: F401
     ChainMeta,
     PaymentRecord,
     PaymentType,

app/wallet_manager_v2.py

@@ -1,6 +1,11 @@
-"""Backward-compat shim — moved to app.wallet.manager in P3B."""
+"""wallet_manager_v2.py - DEPRECATED shim. Use app.domains.wallet.manager.
-from app.wallet.manager import *  # noqa: F401,F403
+
-from app.wallet.manager import (  # noqa: F401
+Phase 4 of AUDIT-2026-Q3.md moved this to app/domains/wallet/manager/.
+This shim re-exports the public surface for legacy callers.
+"""
+from app.domains.wallet.manager import *  # noqa: F401,F403
+from app.domains.wallet.manager import (  # noqa: F401
+    CHAIN_REGISTRY,
     ChainMeta,
     PaymentRecord,
     PaymentType,
@@ -16,5 +21,7 @@ from app.wallet.manager import (  # noqa: F401
     ZKAddressVerifier,
     get_wallet_manager_v2,
     import_legacy_wallets,
+    logger,
     _build_registry,
+    _wallet_manager_instance,
 )