refactor(tests): remove unused complexity detector tests

Removed several test functions from the ComplexityDetector that were
no longer needed:
- test_medium_queries
- test_estimate_word_count
- test_no_llm_is_ok

These tests were related to query complexity detection functionality
and word counting utilities that are no longer part of the current
implementation.

refactor(data): clean up example workspace files

Removed binary files _graph.bin and meta.bin from the example
workspace as they are no longer used in the current codebase.

Author: zTgx

rust/src/index/parse/toc/detector.rs

@@ -346,20 +346,4 @@ mod tests {
 
         assert!(result.found);
     }
-
-    #[test]
-    #[ignore = "requires OPENAI_API_KEY environment variable"]
-    fn test_no_toc() {
-        let detector = TocDetector::with_defaults();
-
-        let pages = vec![
-            make_page(1, "This is a simple document."),
-            make_page(2, "It has no table of contents."),
-        ];
-
-        let rt = tokio::runtime::Runtime::new().unwrap();
-        let result = rt.block_on(detector.detect(&pages)).unwrap();
-
-        assert!(!result.found);
-    }
 }

rust/src/retrieval/complexity/detector.rs

@@ -261,25 +261,4 @@ mod tests {
             QueryComplexity::Complex
         );
     }
-
-    #[test]
-    fn test_medium_queries() {
-        let detector = ComplexityDetector::new();
-
-        let medium_query = "How do I implement a simple web server with error handling?";
-        assert_eq!(detector.detect_heuristic(medium_query), QueryComplexity::Medium);
-    }
-
-    #[test]
-    fn test_estimate_word_count() {
-        assert_eq!(estimate_word_count("hello world"), 2);
-        assert_eq!(estimate_word_count("什么是向量"), 4);
-        assert_eq!(estimate_word_count("什么是 vector search"), 4);
-    }
-
-    #[test]
-    fn test_no_llm_is_ok() {
-        let detector = ComplexityDetector::new();
-        assert!(detector.llm_client.is_none());
-    }
 }