test: 补充全面测试覆盖 (+1400 测试用例)

[afine907]

Summary

为 15 个核心模块补充单元测试和集成测试，测试数量从 787 增长到 2194 (+179%)。

Changes

新增测试模块 (49 个测试文件)

模块	测试文件数	覆盖内容
ops	7	config, dashboard, exporter, metrics, models, report
security	8	denial, enhanced, guards, manager, modes, risk, rule, ssrf
plugin	6	builtin_plugins, config, discovery, hooks, loader, registry
core	6	api_server, database, error_code, monitoring, plugin, webhook
memory	4	long_term, retriever, short_term, types
mcp	2	client, integration
session	3	manager, models, session_manager
models	3	factory, registry, types
context	3	init, lazy_ignore, project
skills	1	builtins
task	1	types
cli	1	main

测试策略

• 每个模块独立测试文件
• Mock 外部依赖 (LLM API, 文件系统, 网络)
• 覆盖正常路径和边界情况
• 异步测试使用 pytest-asyncio

Test Plan

• uv run pytest tests/ -x -q --ignore=tests/test_e2e - 2194 passed
• uv run ruff check tests/ - 0 errors