Wire web view to ingest_by_doi and remove dead helpers from services.py

[AymanL]

Parent PRD

#70

What to build

Update the web view DOI submission to call ingest_by_doi instead of the old run_pipeline. Remove the dead helper functions save_to_s3_and_postgres, fetch_file_and_metadata, and the old run_pipeline from services.py. After this slice, services.py should expose only ingest_by_doi (and save_chunks/add_embeddings if kept as internal utilities).

Acceptance criteria

• The web view DOI form calls ingest_by_doi and the resulting IngestionRun is created correctly
• save_to_s3_and_postgres, fetch_file_and_metadata, and the old run_pipeline are deleted from services.py
• No other callers of the deleted helpers exist in the codebase
• Existing web view tests (if any) still pass

Blocked by

• Blocked by Implement ingest_by_doi: single canonical pipeline with IngestionRun, ParsedArtifact, DocumentChunks #72

User stories addressed

• User story 16
• User story 18