feat: add PDF document recognition with 10-page pre-hook

- Migrate recognition_results table to JSON schema (meta_data + content),
  replacing flat latex/markdown/mathml/mml columns
- Add TaskTypePDF constant and update all formula read/write paths
- Add PDFRecognitionService using pdftoppm (Poppler) for CGO-free page
  rendering; limits processing to first 10 pages (pre-hook)
- Reuse existing downstream OCR endpoint (cloud.texpixel.com) for each
  page image; stores results as [{page_number, markdown}] JSON array
- Add Redis queue + distributed lock for PDF worker goroutine
- Add REST endpoints: POST /v1/pdf/recognition, GET /v1/pdf/recognition/:task_no
- Add .pdf to OSS upload file type whitelist
- Add migrations/pdf_recognition.sql for safe data migration

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/v1/oss/handler.go

@@ -70,7 +70,7 @@ func (h *OSSEndpoint) GetSignatureURL(ctx *gin.Context) {
 		ctx.JSON(http.StatusOK, common.ErrorResponse(ctx, common.CodeParamError, "invalid file name"))
 		return
 	}
-	if !utils.InArray(extend, []string{".jpg", ".jpeg", ".png", ".gif", ".bmp", ".tiff", ".webp"}) {
+	if !utils.InArray(extend, []string{".jpg", ".jpeg", ".png", ".gif", ".bmp", ".tiff", ".webp", ".pdf"}) {
 		ctx.JSON(http.StatusOK, common.ErrorResponse(ctx, common.CodeParamError, "invalid file type"))
 		return
 	}

api/v1/pdf/handler.go

@@ -0,0 +1,95 @@
+package pdf
+
+import (
+	"net/http"
+	"path/filepath"
+	"strings"
+
+	pdfmodel "gitea.com/texpixel/document_ai/internal/model/pdf"
+	"gitea.com/texpixel/document_ai/internal/service"
+	"gitea.com/texpixel/document_ai/pkg/common"
+	"gitea.com/texpixel/document_ai/pkg/constant"
+
+	"github.com/gin-gonic/gin"
+)
+
+type PDFEndpoint struct {
+	pdfService *service.PDFRecognitionService
+}
+
+func NewPDFEndpoint() *PDFEndpoint {
+	return &PDFEndpoint{
+		pdfService: service.NewPDFRecognitionService(),
+	}
+}
+
+// CreateTask godoc
+// @Summary Create a PDF recognition task
+// @Description Create a new PDF recognition task (max 10 pages processed)
+// @Tags PDF
+// @Accept json
+// @Produce json
+// @Param request body pdfmodel.CreatePDFRecognitionRequest true "Create PDF task request"
+// @Success 200 {object} common.Response{data=pdfmodel.CreatePDFTaskResponse}
+// @Failure 400 {object} common.Response
+// @Failure 500 {object} common.Response
+// @Router /v1/pdf/recognition [post]
+func (e *PDFEndpoint) CreateTask(c *gin.Context) {
+	var req pdfmodel.CreatePDFRecognitionRequest
+	if err := c.BindJSON(&req); err != nil {
+		c.JSON(http.StatusOK, common.ErrorResponse(c, common.CodeParamError, "参数错误"))
+		return
+	}
+	req.UserID = c.GetInt64(constant.ContextUserID)
+
+	if strings.ToLower(filepath.Ext(req.FileName)) != ".pdf" {
+		c.JSON(http.StatusOK, common.ErrorResponse(c, common.CodeParamError, "仅支持PDF文件"))
+		return
+	}
+
+	task, err := e.pdfService.CreatePDFTask(c, &req)
+	if err != nil {
+		if bizErr, ok := err.(*common.BusinessError); ok {
+			c.JSON(http.StatusOK, common.ErrorResponse(c, int(bizErr.Code), bizErr.Message))
+			return
+		}
+		c.JSON(http.StatusOK, common.ErrorResponse(c, common.CodeSystemError, "创建任务失败"))
+		return
+	}
+
+	c.JSON(http.StatusOK, common.SuccessResponse(c, &pdfmodel.CreatePDFTaskResponse{
+		TaskNo: task.TaskUUID,
+		Status: int(task.Status),
+	}))
+}
+
+// GetTaskStatus godoc
+// @Summary Get PDF recognition task status and results
+// @Description Poll task status; pages field populated when status=2 (completed)
+// @Tags PDF
+// @Accept json
+// @Produce json
+// @Param task_no path string true "Task No"
+// @Success 200 {object} common.Response{data=pdfmodel.GetPDFTaskResponse}
+// @Failure 404 {object} common.Response
+// @Failure 500 {object} common.Response
+// @Router /v1/pdf/recognition/{task_no} [get]
+func (e *PDFEndpoint) GetTaskStatus(c *gin.Context) {
+	var req pdfmodel.GetPDFTaskRequest
+	if err := c.ShouldBindUri(&req); err != nil {
+		c.JSON(http.StatusOK, common.ErrorResponse(c, common.CodeParamError, "参数错误"))
+		return
+	}
+
+	resp, err := e.pdfService.GetPDFTask(c, req.TaskNo)
+	if err != nil {
+		if bizErr, ok := err.(*common.BusinessError); ok {
+			c.JSON(http.StatusOK, common.ErrorResponse(c, int(bizErr.Code), bizErr.Message))
+			return
+		}
+		c.JSON(http.StatusOK, common.ErrorResponse(c, common.CodeSystemError, "查询任务失败"))
+		return
+	}
+
+	c.JSON(http.StatusOK, common.SuccessResponse(c, resp))
+}