refactor(lite): remove dead backend artifact-contract/resolver scaffold

lite_backend_artifact_{contract,resolver}.{cpp,h} (~1,960 lines) were
app-linked but never invoked: all 14 public entry points
(evaluateLiteBackendArtifactContract/Resolver, evaluateLiteBackendActivation-
Readiness, the resolve*/...Name helpers) had zero callers in the app, the
lite_smoke tool, build scripts, or surviving tests. The real backend load
path (LiteClientBridge::linkedSdxl) uses direct litelib_* externs, and the
DRAGONX_ENABLE_LITE_BACKEND symbol check is done in CMake against the symbols
inventory (FATAL_ERROR on a missing symbol) — not via these C++ files. The
files were saturated with churn markers (disabled / dry-dispatch / scaffold).

- Delete the four artifact files and their 8 CMakeLists references.
- Drop the orphaned test cruft in test_phase4.cpp: the contract include,
  5 type aliases, and 3 never-called helpers (heapConstructPlanResult,
  makeReadyLiteBackendArtifactProvenance, liteBackendArtifactContractHasIssue)
  left over from the already-removed bridge-runtime tests.
- Correct the CLAUDE.md lite-wallet description (it credited these files with
  backend validation that CMake actually performs) and drop the stale
  lite_bridge_runtime mention.

Both variants build; full test suite passes; source-hygiene check clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CMakeLists.txt

@@ -389,8 +389,6 @@ set(APP_SOURCES
     src/services/wallet_security_workflow.cpp
     src/services/wallet_security_workflow_executor.cpp
     src/chat/chat_protocol.cpp
-    src/wallet/lite_backend_artifact_contract.cpp
-    src/wallet/lite_backend_artifact_resolver.cpp
     src/wallet/lite_owned_string.cpp
     src/wallet/lite_client_bridge.cpp
     src/wallet/lite_connection_service.cpp
@@ -505,8 +503,6 @@ set(APP_HEADERS
     src/services/wallet_security_workflow_executor.h
     src/wallet/wallet_capabilities.h
     src/wallet/wallet_backend.h
-    src/wallet/lite_backend_artifact_contract.h
-    src/wallet/lite_backend_artifact_resolver.h
     src/wallet/lite_owned_string.h
     src/wallet/lite_client_bridge.h
     src/wallet/lite_connection_service.h
@@ -693,8 +689,6 @@ if(DRAGONX_LITE_BACKEND_READY)
         tools/lite_smoke.cpp
         src/wallet/lite_client_bridge.cpp
         src/wallet/lite_owned_string.cpp
-        src/wallet/lite_backend_artifact_contract.cpp
-        src/wallet/lite_backend_artifact_resolver.cpp
         src/wallet/lite_connection_service.cpp
         src/wallet/lite_result_parsers.cpp
     )
@@ -939,8 +933,6 @@ if(BUILD_TESTING)
         src/services/wallet_security_workflow.cpp
         src/services/wallet_security_workflow_executor.cpp
         src/chat/chat_protocol.cpp
-        src/wallet/lite_backend_artifact_contract.cpp
-        src/wallet/lite_backend_artifact_resolver.cpp
         src/wallet/lite_owned_string.cpp
         src/wallet/lite_client_bridge.cpp
         src/wallet/lite_connection_service.cpp