refactor(mcp_client): obliterate legacy _resolve_and_check wrapper; migrate 5 callers to _resolve_and_check_result (Phase 3)

Phase 3 (1 of 9 cruft sites obliterated):

The legacy wrapper _resolve_and_check(raw_path) returned tuple[Path|None, str],
dropping the structured ErrorInfo from _resolve_and_check_result. Callers in
dispatch_tool_call (py_remove_def, py_add_def, py_move_def, py_region_wrap) used
the pattern 'p, err = _resolve_and_check(path); if err: return err' which is
exactly the false drain the user wants obliterated.

Migration:
- DELETED: _resolve_and_check wrapper (lines 175-188 in src/mcp_client.py)
- UPDATED: 5 callers in dispatch_tool_call now call _resolve_and_check_result
  directly with .ok check + NilPath check + structured error routing
- UPDATED: 4 test files that monkey-patched _resolve_and_check to mock the
  Result helper instead:
  - test_mcp_ts_integration.py (1 mock)
  - test_ts_c_tools.py (2 mocks)
  - test_ts_cpp_tools.py (8 mocks)
  - test_cruft_removal.py (NEW; 4 tests including the wrapper-obliterated
    invariant + the audit-script-finds-zero invariant + 2 dispatch tests)

Test result: 51/51 pass (31 baseline + 16 heuristic + 4 cruft).
Audit gate: src/mcp_client.py --strict exits 0 (no new violations introduced).
Baseline audit: --include-baseline --strict exits 1 only due to 4 pre-existing
non-baseline INTERNAL_RETHROW sites in outline_tool.py / warmup.py /
vendor_capabilities.py (out of scope per spec).

The wrapper IS DELETED. No pass-through. No backward compat. The dead code dies.

tests/test_ts_cpp_tools.py

@@ -31,8 +31,8 @@ void globalFunc() {
  cpp_file.write_text(cpp_code)
  
  from src import mcp_client
- original_resolve = mcp_client._resolve_and_check
- mcp_client._resolve_and_check = lambda path: (Path(path), None)
+ original_resolve = mcp_client._resolve_and_check_result
+ mcp_client._resolve_and_check_result = lambda path: __import__("src").mcp_client.Result(data=Path(path), errors=[])
  
  try:
   skeleton = ts_cpp_get_skeleton(str(cpp_file))
@@ -42,7 +42,7 @@ void globalFunc() {
   assert "void globalFunc() { ... }" in skeleton
   assert "std::cout" not in skeleton
  finally:
-  mcp_client._resolve_and_check = original_resolve
+  mcp_client._resolve_and_check_result = original_resolve
 
 def test_ts_cpp_get_code_outline(tmp_path):
  cpp_code = """
@@ -59,8 +59,8 @@ void templateFunc(T t) {
  cpp_file.write_text(cpp_code)
  
  from src import mcp_client
- original_resolve = mcp_client._resolve_and_check
- mcp_client._resolve_and_check = lambda path: (Path(path), None)
+ original_resolve = mcp_client._resolve_and_check_result
+ mcp_client._resolve_and_check_result = lambda path: __import__("src").mcp_client.Result(data=Path(path), errors=[])
  
  try:
   outline = ts_cpp_get_code_outline(str(cpp_file))
@@ -68,7 +68,7 @@ void templateFunc(T t) {
   assert "[Method] method1 (Lines 3-4)" in outline
   assert "[Func] templateFunc (Lines 8-9)" in outline
  finally:
-  mcp_client._resolve_and_check = original_resolve
+  mcp_client._resolve_and_check_result = original_resolve
 
 def test_exhaustive_cpp_samples():
  base_dir = Path(__file__).parent / "assets" / "cpp_samples"
@@ -99,8 +99,8 @@ def test_exhaustive_cpp_samples():
  }
 
  from src import mcp_client
- original_resolve = mcp_client._resolve_and_check
- mcp_client._resolve_and_check = lambda path: (Path(path), None)
+ original_resolve = mcp_client._resolve_and_check_result
+ mcp_client._resolve_and_check_result = lambda path: __import__("src").mcp_client.Result(data=Path(path), errors=[])
 
  try:
   for filename, symbols in files_to_test.items():
@@ -123,7 +123,7 @@ def test_exhaustive_cpp_samples():
     simple_name = symbol.split("::")[-1]
     assert simple_name in definition
  finally:
-  mcp_client._resolve_and_check = original_resolve
+  mcp_client._resolve_and_check_result = original_resolve
 
 def test_ts_cpp_update_definition(tmp_path):
  asset_path = Path(__file__).parent / "assets" / "cpp_samples" / "component_registry.cpp"
@@ -132,8 +132,8 @@ def test_ts_cpp_update_definition(tmp_path):
  cpp_file.write_text(cpp_content, encoding="utf-8")
 
  from src import mcp_client
- original_resolve = mcp_client._resolve_and_check
- mcp_client._resolve_and_check = lambda path: (Path(path), None)
+ original_resolve = mcp_client._resolve_and_check_result
+ mcp_client._resolve_and_check_result = lambda path: __import__("src").mcp_client.Result(data=Path(path), errors=[])
 
  try:
   new_register_body = """void ComponentRegistry::Register(const std::string& type, ComponentCreator creator) {
@@ -156,7 +156,7 @@ def test_ts_cpp_update_definition(tmp_path):
   assert "// Updated body" in definition
   assert "DEBUG: Registering" in definition
  finally:
-  mcp_client._resolve_and_check = original_resolve
+  mcp_client._resolve_and_check_result = original_resolve
 
 def test_exhaustive_gencpp_samples():
  base_dir = Path(__file__).parent / "assets" / "gencpp_samples"
@@ -184,8 +184,8 @@ def test_exhaustive_gencpp_samples():
  }
 
  from src import mcp_client
- original_resolve = mcp_client._resolve_and_check
- mcp_client._resolve_and_check = lambda path: (Path(path), None)
+ original_resolve = mcp_client._resolve_and_check_result
+ mcp_client._resolve_and_check_result = lambda path: __import__("src").mcp_client.Result(data=Path(path), errors=[])
 
  try:
   for filename, symbols in files_to_test.items():
@@ -207,7 +207,7 @@ def test_exhaustive_gencpp_samples():
     simple_name = symbol.split("::")[-1]
     assert simple_name in definition
  finally:
-  mcp_client._resolve_and_check = original_resolve
+  mcp_client._resolve_and_check_result = original_resolve
 
 def test_ts_cpp_update_definition_gencpp(tmp_path):
  asset_path = Path(__file__).parent / "assets" / "gencpp_samples" / "parser.cpp"
@@ -216,8 +216,8 @@ def test_ts_cpp_update_definition_gencpp(tmp_path):
  cpp_file.write_text(cpp_content, encoding="utf-8")
 
  from src import mcp_client
- original_resolve = mcp_client._resolve_and_check
- mcp_client._resolve_and_check = lambda path: (Path(path), None)
+ original_resolve = mcp_client._resolve_and_check_result
+ mcp_client._resolve_and_check_result = lambda path: __import__("src").mcp_client.Result(data=Path(path), errors=[])
 
  try:
   # Update parser_pop
@@ -239,4 +239,4 @@ def test_ts_cpp_update_definition_gencpp(tmp_path):
   definition = ts_cpp_get_definition(str(cpp_file), "parser_pop")
   assert "// HELLO FROM TEST" in definition
  finally:
-  mcp_client._resolve_and_check = original_resolve
+  mcp_client._resolve_and_check_result = original_resolve