fix: evaluation report P0/P1/P2 fixes, remove Docker, add upload UI

Backend:
- Add NotFoundException + BusinessException, return correct HTTP status (404/400)
- Add @Index on reports.project_id and reports.upload_time
- Add fileSize column to reports, populate on upload, return in DTO
- Cascade delete: deleting project now removes all reports (DB + files + PDFs)
- Delete report: also clean up pre-rendered PDF
- File upload MIME validation (extension + Content-Type)
- Remove duplicate @ExceptionHandler from ReportController
- Switch from System.err to SLF4J logger
- Handle MethodArgumentNotValid, MissingServletRequestPart, etc.

Frontend:
- Remove all Docker files (project uses 宝塔 panel deployment)
- Upgrade axios 1.6.8 -> 1.7.7 (CVE-2024-39338)
- Remove unused @vue-office/pptx + vue-demi (see CHANGELOG for rationale)
- Fix vite proxy port 37821 -> 30081
- Remove mock data fallback in production
- Add upload report UI (button + modal in ProjectDetail)
- Add create project UI (button + modal in ProjectList)
- Add filename search box in ProjectDetail
- New useApi methods: createProject, uploadReport, deleteProject, deleteReport
- FilePreview/ReportCard: show fileSize (was undefined before)

Docs:
- Add README.md (overview, quick start, structure)
- Add CHANGELOG.md (full change log + pptx removal rationale)
- Include EVALUATION_REPORT.md and blog-vibe-coding.md

Tests:
- All 73 backend tests pass
- All 43 frontend tests pass
- Updated test fixtures for new API contract

src/test/java/com/reportdist/CompleteApiFlowIntegrationTest.java

@@ -240,13 +240,12 @@ class CompleteApiFlowIntegrationTest {
         );
         assertEquals(HttpStatus.NOT_FOUND, getProject.getStatusCode());
 
-        // Reports still exist (they're orphaned - not cascade deleted)
-        // This confirms reports are independent entities
-        ResponseEntity<List> orphanedReports = restTemplate.getForEntity(
-                baseUrl + "/api/reports",
+        // Reports are cascade-deleted along with the project
+        ResponseEntity<List> remainingReports = restTemplate.getForEntity(
+                baseUrl + "/api/reports?projectId=" + projectId,
                 List.class
         );
-        assertTrue(orphanedReports.getBody().size() >= 2);
-        System.out.println("[INFO] Project deleted. Reports remain in database (manual cleanup required).");
+        assertEquals(0, remainingReports.getBody().size());
+        System.out.println("[INFO] Project deleted. All reports cascade-deleted.");
     }
 }