feat(repository): 实现 Gemini OAuth 和 Token 缓存客户端

- 添加 Gemini OAuth 客户端实现
- 实现 Redis 基础的 Token 缓存
- 添加 gemini-cli Code Assist 客户端封装

backend/internal/repository/geminicli_codeassist_client.go

@@ -0,0 +1,95 @@
+package repository
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/geminicli"
+	"github.com/Wei-Shaw/sub2api/internal/service/ports"
+
+	"github.com/imroc/req/v3"
+)
+
+type geminiCliCodeAssistClient struct {
+	baseURL string
+}
+
+func NewGeminiCliCodeAssistClient() ports.GeminiCliCodeAssistClient {
+	return &geminiCliCodeAssistClient{baseURL: geminicli.GeminiCliBaseURL}
+}
+
+func (c *geminiCliCodeAssistClient) LoadCodeAssist(ctx context.Context, accessToken, proxyURL string, reqBody *geminicli.LoadCodeAssistRequest) (*geminicli.LoadCodeAssistResponse, error) {
+	if reqBody == nil {
+		reqBody = defaultLoadCodeAssistRequest()
+	}
+
+	var out geminicli.LoadCodeAssistResponse
+	resp, err := createGeminiCliReqClient(proxyURL).R().
+		SetContext(ctx).
+		SetHeader("Authorization", "Bearer "+accessToken).
+		SetHeader("Content-Type", "application/json").
+		SetHeader("User-Agent", geminicli.GeminiCLIUserAgent).
+		SetBody(reqBody).
+		SetSuccessResult(&out).
+		Post(c.baseURL + "/v1internal:loadCodeAssist")
+	if err != nil {
+		return nil, fmt.Errorf("request failed: %w", err)
+	}
+	if !resp.IsSuccessState() {
+		return nil, fmt.Errorf("loadCodeAssist failed: status %d, body: %s", resp.StatusCode, geminicli.SanitizeBodyForLogs(resp.String()))
+	}
+	return &out, nil
+}
+
+func (c *geminiCliCodeAssistClient) OnboardUser(ctx context.Context, accessToken, proxyURL string, reqBody *geminicli.OnboardUserRequest) (*geminicli.OnboardUserResponse, error) {
+	if reqBody == nil {
+		reqBody = defaultOnboardUserRequest()
+	}
+
+	var out geminicli.OnboardUserResponse
+	resp, err := createGeminiCliReqClient(proxyURL).R().
+		SetContext(ctx).
+		SetHeader("Authorization", "Bearer "+accessToken).
+		SetHeader("Content-Type", "application/json").
+		SetHeader("User-Agent", geminicli.GeminiCLIUserAgent).
+		SetBody(reqBody).
+		SetSuccessResult(&out).
+		Post(c.baseURL + "/v1internal:onboardUser")
+	if err != nil {
+		return nil, fmt.Errorf("request failed: %w", err)
+	}
+	if !resp.IsSuccessState() {
+		return nil, fmt.Errorf("onboardUser failed: status %d, body: %s", resp.StatusCode, geminicli.SanitizeBodyForLogs(resp.String()))
+	}
+	return &out, nil
+}
+
+func createGeminiCliReqClient(proxyURL string) *req.Client {
+	client := req.C().SetTimeout(30 * time.Second)
+	if proxyURL != "" {
+		client.SetProxyURL(proxyURL)
+	}
+	return client
+}
+
+func defaultLoadCodeAssistRequest() *geminicli.LoadCodeAssistRequest {
+	return &geminicli.LoadCodeAssistRequest{
+		Metadata: geminicli.LoadCodeAssistMetadata{
+			IDEType:    "ANTIGRAVITY",
+			Platform:   "PLATFORM_UNSPECIFIED",
+			PluginType: "GEMINI",
+		},
+	}
+}
+
+func defaultOnboardUserRequest() *geminicli.OnboardUserRequest {
+	return &geminicli.OnboardUserRequest{
+		TierID: "LEGACY",
+		Metadata: geminicli.LoadCodeAssistMetadata{
+			IDEType:    "ANTIGRAVITY",
+			Platform:   "PLATFORM_UNSPECIFIED",
+			PluginType: "GEMINI",
+		},
+	}
+}