feat: add import error tracking and translation tabs

Import Error Tracking:
- Add MarketplaceImportError model to store detailed error information
- Store row number, identifier, error type, message, and row data for each error
- Add API endpoint GET /admin/marketplace-import-jobs/{job_id}/errors
- Add UI to view and browse import errors in job details modal
- Support pagination and error type filtering

Translation Tabs:
- Replace flat translation list with tabbed interface on product detail page
- Add language tabs with full language names
- Add copy-to-clipboard functionality for translation content
- Improved UX with better visual separation of translations

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

static/admin/js/imports.js

@@ -54,6 +54,12 @@ function adminImports() {
         showJobModal: false,
         selectedJob: null,
 
+        // Job errors state
+        jobErrors: [],
+        jobErrorsTotal: 0,
+        jobErrorsPage: 1,
+        loadingErrors: false,
+
         // Auto-refresh for active jobs
         autoRefreshInterval: null,
 
@@ -275,6 +281,58 @@ function adminImports() {
         closeJobModal() {
             this.showJobModal = false;
             this.selectedJob = null;
+            // Clear errors state
+            this.jobErrors = [];
+            this.jobErrorsTotal = 0;
+            this.jobErrorsPage = 1;
+        },
+
+        /**
+         * Load errors for a specific job
+         */
+        async loadJobErrors(jobId) {
+            if (!jobId) return;
+
+            this.loadingErrors = true;
+            this.jobErrorsPage = 1;
+
+            try {
+                const response = await apiClient.get(
+                    `/admin/marketplace-import-jobs/${jobId}/errors?page=1&limit=20`
+                );
+                this.jobErrors = response.errors || [];
+                this.jobErrorsTotal = response.total || 0;
+                adminImportsLog.debug('Loaded job errors:', this.jobErrors.length);
+            } catch (error) {
+                adminImportsLog.error('Failed to load job errors:', error);
+                this.error = error.message || 'Failed to load import errors';
+            } finally {
+                this.loadingErrors = false;
+            }
+        },
+
+        /**
+         * Load more errors (pagination)
+         */
+        async loadMoreJobErrors(jobId) {
+            if (!jobId || this.loadingErrors) return;
+
+            this.loadingErrors = true;
+            this.jobErrorsPage++;
+
+            try {
+                const response = await apiClient.get(
+                    `/admin/marketplace-import-jobs/${jobId}/errors?page=${this.jobErrorsPage}&limit=20`
+                );
+                const newErrors = response.errors || [];
+                this.jobErrors = [...this.jobErrors, ...newErrors];
+                adminImportsLog.debug('Loaded more job errors:', newErrors.length);
+            } catch (error) {
+                adminImportsLog.error('Failed to load more job errors:', error);
+                this.jobErrorsPage--; // Revert page on failure
+            } finally {
+                this.loadingErrors = false;
+            }
         },
 
         /**