fetch_content caches full page text to ~/Downloads instead of project cwd

[Dunya-8a]

Summary

When research subagents fetch web/paper content, the fetched full-text page dumps land in ~/Downloads (timestamped, named after the fetched papers) instead of anywhere under the project working directory. They're cache/scratch, not deliverables, but they spill outside the repo and there's no exposed way to redirect them.

What's actually happening (traced through source)

• feynman's own source (src/) has no code that writes fetched content to ~/Downloads and no setting to redirect a fetch cache into cwd. The only homedir() uses in src/ are config dirs (.feynman, .modal.toml, .claude-science).
• The underlying agent @earendil-works/pi-coding-agent has no web-fetch tool at all — its built-in tools are bash/edit/find/grep/ls/read/write.
• The fetch tool is fetch_content (aliased from fetch / WebFetch / read_url_content in @earendil-works/pi-agent-core, see dist/agent-loop.js), registered dynamically at runtime from the Pi/alpha layer. Its write-to-~/Downloads default is not statically configurable from feynman.

Impact

• Fetch cache accumulates in ~/Downloads across runs, mixed with unrelated user files.
• Users can't tell cache from deliverables at a glance (both timestamped "today").
• Cleanup requires touching ~/Downloads, which is undesirable to automate.

Expected

fetch_content should cache fetched page content inside the project working directory (e.g. a gitignored notes/cache/ or .feynman/cache/), or expose a config/env override so feynman can point it at cwd.

Notes

Separate from #187 (that was about the --extensions unknown-flag UX). This is about the fetch cache location.

Environment

• feynman 0.3.5 (darwin-arm64)

[advaitpaliwal]

Fixed and released in v0.3.6. fetch_content scratch Markdown now stays under the active project's .feynman/cache/fetch-content instead of spilling into ~/Downloads. FEYNMAN_FETCH_CACHE_DIR provides an explicit override.

The owning Pi web-access patch is regression-tested and verified in the installed runtime; exact-candidate CI passed in run 30355913177, and post-release identity reconciliation is green in run 30373237537. Closing as completed.