Fix navbar: SVG logos, Settings menu, Logout handler

- Image handler now returns SVG placeholders for company logo and user
  avatars instead of broken 1x1 PNG (fixes yellow border in navbar)
- Supports both query-param (?model=&field=) and path-style URLs
  (/web/image/res.partner/2/avatar_128)
- Added Settings app menu with Users & Technical sub-menus
- Added actions for Settings (company form), Users list, Sequences
- Added /web/session/logout handler that clears session + cookie
- Added logout to middleware whitelist

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pkg/server/middleware.go

@@ -47,6 +47,7 @@ func AuthMiddleware(store *SessionStore, next http.Handler) http.Handler {
 		if path == "/health" ||
 			path == "/web/login" ||
 			path == "/web/session/authenticate" ||
+			path == "/web/session/logout" ||
 			strings.HasPrefix(path, "/web/database/") ||
 			path == "/web/webclient/version_info" ||
 			strings.Contains(path, "/static/") {