Verify: Claim layer — link paper assertions to verification chain

[ywatanabe1989]

Summary

Extend the verify module to track Claim nodes — specific assertions in paper.tex (line numbers, statistics, figure references) linked to their source data in the verification chain.

Current State

The verification chain stops at Output files (CSVs, figures). There's no link from "this p-value appears on line 42 of the manuscript" back to results.csv.

Proposed Changes

1. Add claim role to file_hashes schema
2. Support claim registration: scitex verify add-claim --file paper.tex --line 42 --source results.csv --value "p = 0.003"
3. Support figrecipe claims: scitex verify add-claim --file paper.tex --line 58 --source figure1.yaml --type figure
4. BPV from claims: scitex verify bpv --claim "paper.tex:L42" traces backward to source data

Key Integration Points

• LaTeX line references: Track which line in paper.tex states each claim
• figrecipe recipes: Link figure claims to recipe YAML hashes (figrecipe#98)
• Statistics: Link reported p-values/effect sizes to the script+data that produced them

Motivation

• Closes the loop: Source → Input → Process → Output → Claim (in paper)
• BPV can trace from "p = 0.003 on line 42" all the way back to raw data
• Enables automated checking: "does the value in the manuscript match what the pipeline produced?"

Scope Note

This is an enhancement beyond the current paper's scope. Suitable for Discussion as future work: "The current implementation verifies the computational chain up to output artifacts. Extending to Claim-level verification would enable end-to-end traceability from manuscript text to raw data."