chore: periodic maintenance — deps refresh and spec/doc alignment (#105)

- Refresh Cargo.lock (tokio 1.52, reqwest 0.13.3, rustls 0.23.40, rustls-platform-verifier 0.7, tower-http 0.6.10, pyo3 0.28.3, transitives)
- Align specs/initial.md and README with current FetchRequest/FetchResponse surface (content_focus, conditional-request fields; etag, metadata, word_count, redirect_chain, is_paywall)
- Re-verify threat model (bump Last verified to 2026-05-17)
- Document why release.yml dispatches publish.yml explicitly (default GITHUB_TOKEN limitation)
- Collapse nested if into match arm guards in convert.rs for clippy::collapsible_match (Rust 1.95)

Author: chaliy

CHANGELOG.md

@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- chore(deps): refresh `Cargo.lock` to latest compatible versions (tokio 1.52, reqwest 0.13.3, rustls 0.23.40, tower-http 0.6.10, rustls-platform-verifier 0.7, pyo3 0.28.3, and others)
+- docs: document conditional-request, content-focus, ETag, metadata, word count, redirect chain, and paywall fields in spec and README
+
+### Maintenance
+
+- chore: re-verify threat model (`specs/threat-model.md` Last verified bumped to 2026-05-17)
+
 ## [0.2.0] - 2026-03-27
 
 ### Highlights