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

agent_test/delete_projects.py

@@ -0,0 +1,18 @@
+import urllib.request, json
+
+base = 'https://www.1415243231.top/api'
+
+# Get all projects
+req = urllib.request.urlopen(base + '/projects')
+projects = json.loads(req.read())
+print('Found:', [(p['id'], p['name']) for p in projects])
+
+# Delete each
+for p in projects:
+    try:
+        req = urllib.request.urlopen(
+            urllib.request.Request(base + '/projects/' + str(p['id']), method='DELETE')
+        )
+        print('Deleted %s: %s (%s)' % (p['id'], p['name'], req.status))
+    except Exception as e:
+        print('Error deleting %s: %s' % (p['id'], e))