[Feature] BibTeX Importer UI & Workspace Document Viewer

[JonnyTran]

Summary

The Papers Library Importer allows researchers to bulk import documents into an Extralit workspace by uploading a .bib file and a folder of PDFs. It provides:

• Analysis Phase: Parse bibliographic entries and match PDFs to references; classify as add/update/skip/failed.
• Preview Phase: Display a reviewable table of import candidates with metadata and status, and allow action overrides.
• Execution Phase: Perform asynchronous bulk upsert (add or update documents), upload PDFs to S3, and track progress via real-time job updates.
• Integration: Persist structured bibliographic metadata, tag imports by collection and source, and surface imported documents alongside existing ones.

Key Requirements

1. Metadata Extraction & Matching

   • Parse .bib entries (title, authors, year, DOI/PMID, reference key).
   • Match PDF filenames to entries (exact, partial, or fuzzy match).
   • Tag unmatched or failed PDFs.

2. Preview & Confirmation

   • Show import preview table with reference key, title, authors, year, files, and status.
   • Allow users to override add/update/skip on a per‐document basis.

3. Bulk Import Execution

   • Asynchronously upsert documents and upload files in batches (20–50 per request).
   • Track progress and report summary counts (added, updated, skipped, failed).
   • Continue processing on individual errors; report specific failures.

4. Workspace Integration

   • Store bibliographic metadata in Document records (reference key, DOI, PMID).
   • Add collections and source: "bib_import" tags to imported documents.
   • Ensure imported documents appear with existing documents for extraction workflows.

5. Error Handling & Security

   • Provide clear errors for malformed BibTeX, unreadable PDFs, upload failures, duplicates, and quota issues.
   • Validate file types/sizes, sanitize BibTeX input, and integrate virus scanning.
   • Support retry and resume for interrupted imports.

Acceptance Criteria

• POST /imports/analyze returns status for each entry.
• Preview UI displays editable import actions.
• POST /documents/bulk enqueues upload jobs and returns job IDs.
• Progress UI tracks jobs in real time and handles errors.
• Imported documents carry correct metadata and tags.
• Comprehensive unit/integration tests for all phases.

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Files & Components

• Backend: handlers (imports.py, documents.py), contexts (imports.py), jobs (document_jobs.py), ImportHistory model.
• Frontend: Vue components ImportUpload.vue, ImportPreview.vue, ImportProgress.vue, ImportResults.vue, and the page at pages/workspace/_id/import.vue.
• Schemas: Pydantic models for ImportAnalysisRequest/Response, BulkUploadMetadata, and ImportHistory DB schema.

[JonnyTran]

Finished with PR #107