fix(editor): remove dangling Header 'Profile' toggle

P0-7: the Project Editor's header-section exposed a 'Profile'
toggle (HeaderConfig.showProfile) with no corresponding UI anywhere
in the storefront header — confirmed dead per docs/KNOWN-ISSUES.md
item 5. Toggling it implied a feature (an account/profile menu)
that doesn't exist, which is misleading in the editor.

Building the actual account/profile surface is real feature work
(out of scope for this polish pass), so removed the toggle from the
editor's items list and the field-schema registry instead of
building UI a merchant would flip with no visible effect. The
underlying HeaderConfig.showProfile field and its false default are
unchanged (data model untouched, still available if a future
account feature wires it up).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/features/project-editor/sections/header-section.component.ts

@@ -27,7 +27,6 @@ export class ProjectEditorHeaderSectionComponent {
     { key: 'showCategories', label: 'builder.showCategories', descKey: 'builder.showCategoriesDesc' },
     { key: 'showLanguages', label: 'builder.showLanguages', descKey: 'builder.showLanguagesDesc' },
     { key: 'showCart', label: 'builder.showCart', descKey: 'builder.showCartDesc' },
-    { key: 'showProfile', label: 'builder.showProfile', descKey: 'builder.showProfileDesc' },
     { key: 'showWishlist', label: 'builder.showWishlist', descKey: 'builder.showWishlistDesc' },
     { key: 'showCompare', label: 'builder.showCompare', descKey: 'builder.showCompareDesc' },
     { key: 'showRegion', label: 'builder.showRegion', descKey: 'builder.showRegionDesc' },