test: Phase 6 全功能测试 — 19个测试全部通过 + 开发路线文档

- host: 沙箱执行/命令拦截/超时/文件读写/系统信息/路径验证 (6 tests)
- rag: 文本分块/余弦相似度/关键词匹配/文档索引+搜索 (4 tests)
- tools: host_exec/host_file/host_system/knowledge_search/knowledge_ingest (5 tests)
- vision: 图片编码/错误处理/定义验证/执行流程 (4 tests)
- Embedder 重构为接口，支持 API 和 Simple 两种实现
- 添加 ROADMAP.md 未来开发路线

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/ai-core/internal/rag/embedder.go

@@ -10,8 +10,15 @@ import (
 	"time"
 )
 
-// Embedder creates text embeddings using an LLM API.
-type Embedder struct {
+// Embedder is the interface for text embedding.
+type Embedder interface {
+	Embed(ctx context.Context, text string) ([]float64, error)
+	EmbedBatch(ctx context.Context, texts []string) ([]float64, error)
+	IsAvailable() bool
+}
+
+// APIEmbedder creates text embeddings using an LLM API.
+type APIEmbedder struct {
 	baseURL    string
 	apiKey     string
 	model      string
@@ -19,8 +26,8 @@ type Embedder struct {
 }
 
 // NewEmbedder creates a new embedding service.
-func NewEmbedder(baseURL, apiKey, model string) *Embedder {
-	return &Embedder{
+func NewEmbedder(baseURL, apiKey, model string) *APIEmbedder {
+	return &APIEmbedder{
 		baseURL: baseURL,
 		apiKey:  apiKey,
 		model:   model,
@@ -58,12 +65,12 @@ type embeddingError struct {
 }
 
 // Embed generates an embedding vector for the given text.
-func (e *Embedder) Embed(ctx context.Context, text string) ([]float64, error) {
+func (e *APIEmbedder) Embed(ctx context.Context, text string) ([]float64, error) {
 	return e.EmbedBatch(ctx, []string{text})
 }
 
 // EmbedBatch generates embeddings for multiple texts.
-func (e *Embedder) EmbedBatch(ctx context.Context, texts []string) ([]float64, error) {
+func (e *APIEmbedder) EmbedBatch(ctx context.Context, texts []string) ([]float64, error) {
 	if !e.IsAvailable() {
 		return nil, fmt.Errorf("embedding service not available: no API key configured")
 	}
@@ -113,6 +120,6 @@ func (e *Embedder) EmbedBatch(ctx context.Context, texts []string) ([]float64, e
 }
 
 // IsAvailable checks if the embedding service is configured.
-func (e *Embedder) IsAvailable() bool {
+func (e *APIEmbedder) IsAvailable() bool {
 	return e.apiKey != "" && e.baseURL != ""
 }