Closes#168 by the route-split path from #194's review. #167 put PUT
/canvas/viewport behind strict AdminAuth, breaking canvas drag/zoom
persist because the canvas uses session cookies not bearer tokens.
New narrow middleware CanvasOrBearer:
- Accepts a valid bearer (same contract as AdminAuth) OR
- Accepts a request whose Origin exactly matches CORS_ORIGINS
- Lazy-bootstrap fail-open preserved for fresh installs
Applied ONLY to PUT /canvas/viewport. The softer check is acceptable
there because viewport corruption is cosmetic-only — worst case a
user refreshes the page. This middleware must NOT be used on routes
that leak prompts (#165), create resources (#164), or write files
(#190) — see #194 review for why.
The other canvas-facing routes mentioned in #168 (Events tab, Bundle
Export/Import) remain behind strict AdminAuth pending a proper
session-cookie-accepting AdminAuth (#168 follow-up for Phase H).
6 new tests cover: bootstrap fail-open, no-creds 401, canvas origin
match, wrong origin 401, empty origin rejected, localhost default.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
7a16eb4f70