fix: preserve context warnings on direct lookup

[Destynova2]

Summary

• keep context-window compact warning metadata when dispatch falls back to legacy direct provider lookup
• add a regression test for the direct lookup path
• sync docs with the current max_body_size default

Validation

• cargo fmt --all -- --check
• cargo clippy -- -D warnings
• cargo test --lib
• cargo test --doc
• markdownlint-cli2 docs/**/*.md README.md CLAUDE.md
• lychee docs/**/*.md README.md CLAUDE.md
• jq validation for Grafana dashboards

[github-actions]

Mutation testing (PR diff sample)

Informational — never blocks merge. Full matrix runs on main.

Metric	Value
Status	timed-out
Duration	1500 s
Total	61
Caught	0
Missed	0
Timeout	0
Unviable	0

Legend: clean (no survivors), missed (inspect artifact), timed-out (25 min cap reached).

Artifact: mutants-pr-results-fe045aca741664662710cf49d8fac5169d8e6337.