* feat(auth): migrate auth token to HttpOnly cookie & implement WebSocket Origin whitelist
Security improvements from the MUL-566 audit report:
1. Auth token is now set as an HttpOnly, SameSite=Lax cookie on login,
preventing XSS-based token theft. Cookie-based auth includes CSRF
protection via double-submit cookie pattern. The Authorization header
path is preserved for Electron desktop app and CLI/PAT clients.
2. WebSocket upgrader now validates the Origin header against a
configurable allowlist (ALLOWED_ORIGINS env var), rejecting
connections from unauthorized origins.
Backend: new auth cookie helpers, middleware reads cookie as fallback,
WS handler accepts cookie auth, Origin whitelist, logout endpoint.
Frontend: CSRF token in API headers, cookie-aware auth store and WS
client, web app opts into cookieAuth mode while desktop keeps tokens.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
* fix(auth): address PR review — Strict cookies, HMAC-bound CSRF, origin sync
1. SameSite=Lax → SameSite=Strict per spec requirement
2. CSRF token now HMAC-signed with auth token (nonce.signature format),
preventing subdomain cookie injection attacks
3. allowedWSOrigins uses atomic.Value to eliminate data race
4. Removed magic "cookie" sentinel string in WSProvider — pass null token
and guard with boolean check instead
5. Removed dead delete uploadHeaders["Content-Type"] in API client
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
