Robustness: Unwrap() Calls in Index Pipeline and PDF Parser May Cause Panic

[zTgx]

Description

Multiple unwrap() calls exist in the codebase, which may cause panic instead of returning errors when encountering abnormal inputs.

Key Locations:

1. agent/worker/execute.rs — ctx.node_title(entry.node_id).unwrap_or("unknown") (safe here, uses unwrap_or)
2. Various stages in the index/ pipeline — some unwrap() calls in configuration parsing and PDF processing
3. command.rs:110 — n.parse().unwrap_or(20) (safe here, uses unwrap_or)
4. client/engine.rs — Error propagation chain in index_and_persist()

Recommendations

1. Audit unwrap() calls in the index/ and storage/ modules.
2. Replace with the ? operator or the .ok_or(Error::...)? pattern.
3. Add input validation for the PDF parser to avoid panics caused by malformed input.
4. Use the unwrap_used lint from cargo clippy to assist in identification.