fix(mcp,store): address QA round 2

- Fix handle_get_code_snippet inline store-NULL check to return the same
  JSON error format as REQUIRE_STORE and the other inline checks:
  {"error":"no project loaded"} instead of a plain string
- Fix smoke_guard.sh query_graph invocation: pass "query" parameter
  (not "cypher") to match what handle_query_graph actually reads; the
  wrong key caused the handler to early-return before reaching the guard
- Remove extra blank line in handle_get_graph_schema guard block

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: shanemccarron-maker

src/mcp/mcp.c

@@ -1065,7 +1065,6 @@ static char *handle_get_architecture(cbm_mcp_server_t *srv, const char *args) {
         return not_indexed;
     }
 
-
     cbm_schema_info_t schema = {0};
     cbm_store_get_schema(store, project, &schema);
 
@@ -1635,7 +1634,7 @@ static char *handle_get_code_snippet(cbm_mcp_server_t *srv, const char *args) {
     if (!store) {
         free(qn);
         free(project);
-        return cbm_mcp_text_result("no project loaded — run index_repository first", true);
+        return cbm_mcp_text_result("{\"error\":\"no project loaded\"}", true);
     }
 
     char *not_indexed = verify_project_indexed(store, project);

tests/smoke_guard.sh

@@ -63,7 +63,7 @@ check_handler() {
 
 # ── Step 3: Test all 5 guarded handlers ───────────────────────────
 check_handler "search_graph" "{\"project\":\"$FAKE_PROJECT\",\"name_pattern\":\".*\"}"
-check_handler "query_graph"  "{\"project\":\"$FAKE_PROJECT\",\"cypher\":\"MATCH (n) RETURN n LIMIT 1\"}"
+check_handler "query_graph"  "{\"project\":\"$FAKE_PROJECT\",\"query\":\"MATCH (n) RETURN n LIMIT 1\"}"
 check_handler "get_graph_schema" "{\"project\":\"$FAKE_PROJECT\"}"
 check_handler "trace_call_path" "{\"project\":\"$FAKE_PROJECT\",\"function_name\":\"main\",\"direction\":\"both\",\"depth\":1}"
 check_handler "get_code_snippet" "{\"project\":\"$FAKE_PROJECT\",\"qualified_name\":\"main\"}"