refactor: 移除图索引功能，修复内存泄露，优化嵌入生成

主要更改:

1. 移除图索引功能 (graph indexing)
   - 删除 graph_analyzer.py 及相关迁移文件
   - 移除 CLI 的 graph 命令和 --enrich 标志
   - 清理 chain_search.py 中的图查询方法 (370行)
   - 删除相关测试文件

2. 修复嵌入生成内存问题
   - 重构 generate_embeddings.py 使用流式批处理
   - 改用 embedding_manager 的内存安全实现
   - 文件从 548 行精简到 259 行 (52.7% 减少)

3. 修复内存泄露
   - chain_search.py: quick_search 使用 with 语句管理 ChainSearchEngine
   - embedding_manager.py: 使用 with 语句管理 VectorStore
   - vector_store.py: 添加暴力搜索内存警告

4. 代码清理
   - 移除 Symbol 模型的 token_count 和 symbol_type 字段
   - 清理相关测试用例

测试: 760 passed, 7 skipped

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

codex-lens/src/codexlens/cli/output.py

@@ -122,68 +122,3 @@ def render_file_inspect(path: str, language: str, symbols: Iterable[Symbol]) ->
     console.print(header)
     render_symbols(list(symbols), title="Discovered Symbols")
 
-
-def render_graph_results(results: list[dict[str, Any]], *, query_type: str, symbol: str) -> None:
-    """Render semantic graph query results.
-
-    Args:
-        results: List of relationship dicts
-        query_type: Type of query (callers, callees, inheritance)
-        symbol: Symbol name that was queried
-    """
-    if not results:
-        console.print(f"[yellow]No {query_type} found for symbol:[/yellow] {symbol}")
-        return
-
-    title_map = {
-        "callers": f"Callers of '{symbol}' ({len(results)} found)",
-        "callees": f"Callees of '{symbol}' ({len(results)} found)",
-        "inheritance": f"Inheritance relationships for '{symbol}' ({len(results)} found)"
-    }
-
-    table = Table(title=title_map.get(query_type, f"Graph Results ({len(results)})"))
-
-    if query_type == "callers":
-        table.add_column("Caller", style="green")
-        table.add_column("File", style="cyan", no_wrap=False, max_width=40)
-        table.add_column("Line", justify="right", style="yellow")
-        table.add_column("Type", style="dim")
-
-        for rel in results:
-            table.add_row(
-                rel.get("source_symbol", "-"),
-                rel.get("source_file", "-"),
-                str(rel.get("source_line", "-")),
-                rel.get("relationship_type", "-")
-            )
-
-    elif query_type == "callees":
-        table.add_column("Target", style="green")
-        table.add_column("File", style="cyan", no_wrap=False, max_width=40)
-        table.add_column("Line", justify="right", style="yellow")
-        table.add_column("Type", style="dim")
-
-        for rel in results:
-            table.add_row(
-                rel.get("target_symbol", "-"),
-                rel.get("target_file", "-") if rel.get("target_file") else rel.get("source_file", "-"),
-                str(rel.get("source_line", "-")),
-                rel.get("relationship_type", "-")
-            )
-
-    else:  # inheritance
-        table.add_column("Derived Class", style="green")
-        table.add_column("Base Class", style="magenta")
-        table.add_column("File", style="cyan", no_wrap=False, max_width=40)
-        table.add_column("Line", justify="right", style="yellow")
-
-        for rel in results:
-            table.add_row(
-                rel.get("source_symbol", "-"),
-                rel.get("target_symbol", "-"),
-                rel.get("source_file", "-"),
-                str(rel.get("source_line", "-"))
-            )
-
-    console.print(table)
-