Document fuzz test file download in the CLI docs

[robotrobo]

Follows olympix/olympix-dotnet#1739, which makes the generated fuzz test sources retrievable from the CLI instead of email-only.

Changes

cli/agent-mode.md (fuzz agent protocol)

• fuzz_test_results sample gains tests_path / tests_file_count, and download_tests in its actions list.
• New Generated test files subsection: the CLI auto-downloads the sources into fuzz_tests_<session-id>/ and emits fuzz_tests_downloaded before fuzz_test_results; download_tests re-downloads; a session with no stored files reports progress, not error.
• File Output section notes results.json's tests_path and that generated artifacts land in the working directory, not under .opix/agent/.

cli/interactive-mode.md

• New Fuzz test results menu table, including the new [2] Download Generated Test Files entry.

cli/index.mdx

• connect-fuzz-session description and the Fuzz Tests Generation Options blurb mention downloading the test files.

Testing

• npx astro check — 0 errors, 0 warnings (the 172 hints all come from the checked-in venv/ mkdocs JS, pre-existing)
• npm run build — 19 pages built, complete

package.json / package-lock.json are intentionally left out of this PR: astro check added @astrojs/check + typescript locally. Happy to include that dep bump as a follow-up if wanted.

🤖 Generated with Claude Code

https://claude.ai/code/session_012fD1qwff1BRJvVYrtHwJXN