Artifact windows: download the standalone HTML

[dotdevdotdev]

Goal

Artifacts (~/.agentwire/artifacts/<slug>/, rendered in sandboxed iframe windows) are self-contained HTML, but the portal offers no way to save one out — no download affordance exists anywhere in static JS or routes today. Add a download button to the artifact window chrome that serves the file with Content-Disposition: attachment so any artifact can be pulled out as a standalone .html (shareable, archivable). Needed generally, and specifically by the council-minutes artifact (#next).

Scope

• Route: authenticated download endpoint for an artifact's HTML (reuse the existing artifact-serving path + token model — mind the Isolate artifact iframes in an opaque origin (srcdoc) — portal token-theft hardening #645 hardening: keep the iframe srcdoc/sandbox model untouched, download is a separate top-level fetch via apiFetch/token, path-validated to the artifacts root).
• UI: download icon in the artifact WinBox titlebar/controls (agentwire-desktop-ui skill conventions).
• Multi-file artifact dirs: download the entry HTML (index/entry file); if assets exist alongside, either inline or zip — pick simplest honest option and document it.
• Tests for the route (auth required, traversal rejected).

Verification

Open an artifact window → click download → get a working standalone .html; unauthenticated/traversal requests 401/400.

Built by dotdev.dev

[dotdevdotdev]

Implemented in PR #709 (draft).

What shipped:

• GET /api/artifacts/download/{path} in routes/artifacts.py — authenticated (standard bearer middleware), Content-Disposition: attachment, path-validated via resolve + relative_to against the artifacts root (symlink escapes rejected too). Traversal → 400, missing → 404.
• Titlebar download button on local-artifact windows (artifact-window.js), following the .wb-title-ptt titlebar-control convention. Fetches via apiFetch → blob save (a plain link can't carry the bearer token). External-URL artifacts get no button. Isolate artifact iframes in an opaque origin (srcdoc) — portal token-theft hardening #645 srcdoc/sandbox model untouched — download is a separate top-level fetch.

Decision locked (multi-file dirs): download the entry HTML only, no zip/inlining — consistent with the srcdoc rendering contract where relative sub-resources don't resolve anyway; self-contained HTML is the supported shape. Documented in the handler docstring.

Surprise: literal %2e%2e traversal never reaches the handler — yarl dot-segment-normalizes it client-side (it resolved to the DELETE-only {filename} resource → 405). The real vector is encoded-slash ..%2f, which is what the test exercises (guard fires, 400 with invalid path).

Verified: full pytest suite 2534 passed in-worktree; route-snapshot baseline updated deliberately. Live click-path needs rebuild+restart → post-merge.