feat: P1 合盘/星座/问答与测测完整设计包及模拟器取证工具

落地 synastry/star/ask API 与 H5 页面，补齐 cece-frontend-re complete-design 证据文档，并加入 Android 模拟器截图抓取脚本。

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/internal/llm/deepseek/client.go

@@ -0,0 +1,118 @@
+// Package deepseek calls DeepSeek OpenAI-compatible Chat Completions API.
+package deepseek
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"github.com/yuxingu/digital-psychology/apps/api/internal/config"
+)
+
+// Message is one chat turn.
+type Message struct {
+	Role    string `json:"role"`
+	Content string `json:"content"`
+}
+
+// Client talks to DeepSeek.
+type Client struct {
+	cfg    config.DeepSeekConfig
+	http   *http.Client
+}
+
+// New builds a client from config.
+func New(cfg config.DeepSeekConfig) *Client {
+	sec := cfg.TimeoutSec
+	if sec <= 0 {
+		sec = 60
+	}
+	return &Client{
+		cfg: cfg,
+		http: &http.Client{
+			Timeout: time.Duration(sec) * time.Second,
+		},
+	}
+}
+
+// Enabled mirrors config.
+func (c *Client) Enabled() bool {
+	return c != nil && c.cfg.Enabled()
+}
+
+type chatRequest struct {
+	Model    string    `json:"model"`
+	Messages []Message `json:"messages"`
+	Stream   bool      `json:"stream"`
+}
+
+type chatResponse struct {
+	Choices []struct {
+		Message Message `json:"message"`
+	} `json:"choices"`
+	Error *struct {
+		Message string `json:"message"`
+	} `json:"error"`
+}
+
+// Chat sends messages and returns assistant text.
+func (c *Client) Chat(ctx context.Context, messages []Message) (string, error) {
+	if !c.Enabled() {
+		return "", fmt.Errorf("deepseek api_key not configured")
+	}
+	base := c.cfg.BaseURL
+	if base == "" {
+		base = "https://api.deepseek.com"
+	}
+	model := c.cfg.Model
+	if model == "" {
+		model = "deepseek-chat"
+	}
+
+	body, err := json.Marshal(chatRequest{Model: model, Messages: messages, Stream: false})
+	if err != nil {
+		return "", err
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, base+"/chat/completions", bytes.NewReader(body))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("Authorization", "Bearer "+c.cfg.APIKey)
+
+	res, err := c.http.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer res.Body.Close()
+	raw, err := io.ReadAll(io.LimitReader(res.Body, 2<<20))
+	if err != nil {
+		return "", err
+	}
+	var out chatResponse
+	if err := json.Unmarshal(raw, &out); err != nil {
+		return "", fmt.Errorf("deepseek decode: %w body=%s", err, truncate(string(raw), 200))
+	}
+	if out.Error != nil && out.Error.Message != "" {
+		return "", fmt.Errorf("deepseek: %s", out.Error.Message)
+	}
+	if res.StatusCode >= 300 {
+		return "", fmt.Errorf("deepseek HTTP %d: %s", res.StatusCode, truncate(string(raw), 200))
+	}
+	if len(out.Choices) == 0 || strings.TrimSpace(out.Choices[0].Message.Content) == "" {
+		return "", fmt.Errorf("deepseek empty choices")
+	}
+	return strings.TrimSpace(out.Choices[0].Message.Content), nil
+}
+
+func truncate(s string, n int) string {
+	if len(s) <= n {
+		return s
+	}
+	return s[:n] + "…"
+}