fix(mcp_client): add missing ts_c_get_skeleton function

Commit 3bb850ac added tests/test_ts_c_tools.py but the corresponding ts_c_get_skeleton function was never added to src/mcp_client.py. The test file's module-level 'from src.mcp_client import ts_c_get_skeleton, ts_c_get_code_outline' raises ImportError, which aborts Batch 9 collection in run_tests_batched.py.

Add ts_c_get_skeleton parallel to ts_cpp_get_skeleton (commit 3bb850ac also added ts_cpp_get_skeleton). Implementation is the same pattern: parse via ASTParser('c') (which is supported per Phase 2B) and delegate to parser.get_skeleton().

The C function block in mcp_client.py now mirrors the CPP block:
  ts_c_get_skeleton, ts_c_get_code_outline, ts_c_get_definition, ts_c_get_signature, ts_c_update_definition
  ts_cpp_get_skeleton, ts_cpp_get_code_outline, ts_cpp_get_definition, ts_cpp_get_signature, ts_cpp_update_definition

Verified: tests/test_ts_c_tools.py 2/2 pass (previously aborted Batch 9 with ImportError).

src/mcp_client.py

@@ -376,6 +376,23 @@ def get_git_diff(path: str, base_rev: str = "HEAD", head_rev: str = "") -> str:
  
 #region: C
 
+def ts_c_get_skeleton(path: str) -> str:
+ """
+  Returns a skeleton of a C file.
+  [C: tests/test_ts_c_tools.py:test_ts_c_get_skeleton]
+ """
+ p, err = _resolve_and_check(path)
+ if err: return err
+ assert p is not None
+ if not p.exists(): return f"ERROR: file not found: {path}"
+ try:
+  from src.file_cache import ASTParser
+  code = p.read_text(encoding="utf-8")
+  parser = ASTParser("c")
+  return parser.get_skeleton(code, path=str(p))
+ except Exception as e:
+  return f"ERROR generating skeleton for '{path}': {e}"
+
 def ts_c_get_code_outline(path: str) -> str:
  """
   Returns a hierarchical outline of a C file.