feat(asl): Week 2 Day 2 - Excel import with template download and intelligent dedup

Features:
- feat: Excel template generation and download (with examples)
- feat: Excel file parsing in memory (cloud-native, no disk write)
- feat: Field validation (title + abstract required)
- feat: Smart deduplication (DOI priority + Title fallback)
- feat: Literature preview table with statistics
- feat: Complete submission flow (create project + import literatures)

Components:
- feat: Create excelUtils.ts with full Excel processing toolkit
- feat: Enhance TitleScreeningSettings page with upload/preview/submit
- feat: Update API interface signatures and export unified aslApi object

Dependencies:
- chore: Add xlsx library for Excel file processing

Ref: Week 2 Frontend Development - Day 2
Scope: ASL Module MVP - Title Abstract Screening
Cloud-Native: Memory parsing, no file persistence

docs/00-系统总体设计/99-下一步行动决策建议.md

@@ -632,3 +632,4 @@ Day 6（测试验证）：
 
 
 
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