新增: AST代码智能Phase2(read_symbol drill下钻+调用点带行+prompt优先引导)

code_intel: read_symbol 加 drill(目标节点子树递归找嵌套子定义,命中走full)/calls 每项带 line号(与start_row同口径,Vue切段偏移自动对齐)/2 新测试(drill命中+drill_not_found兜底)
prompt: 中英能力列表加 read_symbol 优先引导(治 read_file 全文回灌 prompt 爆)+ 修支持集标错bug(.rs/.ts等原标不支持实为支持集)
tool_registry: read_symbol schema 加 drill 参数 + read_file desc 反向引导
密度: code_intel.rs 全文 25733B vs 骨架 1348B → 降 19.1x;16 单测全绿

src-tauri/src/commands/ai/prompt.rs

@@ -69,6 +69,7 @@ fn system_prompt_parts(lang: &str) -> (&'static str, &'static str, &'static str)
              - Create/query projects, tasks, and ideas\n\
              - Run workflows\n\
              - Read file contents, list directories, create/write files\n\
+             - To understand/locate a code symbol (function/struct/class) prefer read_symbol(path, symbol): returns a skeleton (signature + line range + internal calls, minimal and high-density), avoiding read_file dumping the whole file into the prompt; pass full=true for the full definition body; read_symbol supports .rs/.ts/.tsx/.js/.jsx/.vue — fall back to read_file only for other languages or when the symbol is not found\n\
              - Get file metadata (size, line count, binary detection)\n\
              - Append content to files, search files by name pattern\n\n\
              ## Guidelines\n\
@@ -92,6 +93,7 @@ fn system_prompt_parts(lang: &str) -> (&'static str, &'static str, &'static str)
              - 创建/查询项目、任务、灵感\n\
              - 运行工作流\n\
              - 读取文件内容、列出目录、创建/写入文件\n\
+             - 理解/定位代码符号（函数/结构体/类等）优先用 read_symbol(path, symbol)：返回骨架（签名+行范围+内部调用，极小高密度），避免 read_file 全文回灌撑爆 prompt；需完整定义体传 full=true；read_symbol 支持 .rs/.ts/.tsx/.js/.jsx/.vue，其他语言或未找到符号时再退回 read_file\n\
              - 获取文件元信息（大小、行数、二进制检测）\n\
              - 追加写入文件、按名称模式搜索文件\n\n\
              ## 行为准则\n\