docs(unit-3): Revert to open questions in functional design plan

Functional design documents were written based on self-answered questions
instead of asking the user. Removed pre-written docs and restored the plan
with open questions for the user to answer.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

aidlc-docs/features/cms-frontend/construction/plans/unit-3-functional-design-plan.md

@@ -1,6 +1,6 @@
 # Functional Design Plan — Unit 3: Layout & Navigation
 
-**Status**: ✅ Complete
+**Status**: 📋 Awaiting answers
 
 ## Unit Context
 - **Unit**: Unit 3 — Layout & Navigation
@@ -8,30 +8,67 @@
 - **Depends on**: Unit 2 (AuthContext, RoleGuard, useAuth)
 - **Stories Covered**: US-08 (layout shell), US-18 (role-filtered sidebar), US-19 (theme toggle)
 
-## Design Decisions
+---
 
-### Q1: Topbar
-Remove the Topbar entirely on desktop. A slim mobile-only bar replaces it.
-**Decision**: Remove — all chrome moves into the sidebar.
+Please answer the following questions by filling in the letter after each `[Answer]:` tag.
 
-### Q2: Mobile navigation
-Use a slide-over sidebar overlay triggered by a hamburger button in the mobile bar.
-**Decision**: Sidebar overlay (not bottom nav, not icon-only collapse).
+## Question 1: Topbar
+The current Topbar contains only the LanguageSwitcher and UserMenu.
 
-### Q3: Theme toggle placement
-Sidebar footer (bottom of sidebar), visible on all screen sizes.
-**Decision**: Sidebar footer.
+A) Remove the Topbar entirely — move LanguageSwitcher and UserMenu to the sidebar footer (recommended — sidebar becomes the only chrome, full width for page content)
+B) Keep the Topbar — move LanguageSwitcher and UserMenu to the sidebar footer, leave Topbar as an empty placeholder for future use
+C) Keep the Topbar with its current content, only add the same items also to the sidebar
 
-### Q4: Theme initialisation (no flash)
-Blocking inline script in `index.html` applies theme class before React hydrates.
-**Decision**: Inline script in `index.html`.
+[Answer]:
 
-### Q5: Language switcher placement
-Move from Topbar to sidebar footer alongside theme toggle and UserMenu.
-**Decision**: Sidebar footer.
+---
 
-## Artefacts Produced
-- `unit-3/functional-design/business-rules.md` — BR-U3-01 through BR-U3-15
-- `unit-3/functional-design/domain-entities.md` — NavItem, Role, Theme, SupportedLanguage
-- `unit-3/functional-design/business-logic-model.md` — component hierarchy, theme init, nav filtering, mobile state
-- `unit-3/functional-design/frontend-components.md` — all modified/new/removed components with testIds
+## Question 2: Mobile navigation
+On small screens (< 768px) the sidebar is currently hidden. How should navigation work on mobile?
+
+A) Slide-over overlay — hamburger button in a slim top bar opens the full sidebar as an overlay (recommended)
+B) Bottom navigation bar — fixed bar at the bottom of the screen with icons only
+C) Icon-only sidebar — sidebar collapses to icon-only width on mobile, expands on hover/click
+
+[Answer]:
+
+---
+
+## Question 3: Theme toggle (dark/light mode)
+US-19 requires a theme toggle. Where should it live?
+
+A) Sidebar footer — next to LanguageSwitcher and UserMenu (recommended — keeps all UI controls in one place)
+B) Top of the sidebar — visible without scrolling
+C) Only accessible from the Profile page (not in the sidebar)
+
+[Answer]:
+
+---
+
+## Question 4: Theme — no-flash initialisation
+To avoid a flash of the wrong theme on page load, the theme needs to be applied before React hydrates.
+
+A) Inline script in `index.html` — runs synchronously before React loads (recommended — standard approach, zero dependencies)
+B) CSS-only — use `prefers-color-scheme` media query only, no localStorage persistence
+C) Skip no-flash for now — accept a brief flash on load
+
+[Answer]:
+
+---
+
+## Question 5: Role-filtered sidebar
+The sidebar should only show nav items the current user is allowed to access (US-18). Items per role:
+
+| Item | Owner | Admin | User |
+|---|---|---|---|
+| Dashboard | ✅ | ✅ | ✅ |
+| User Management | ✅ | ✅ | ❌ |
+| System Settings | ✅ | ❌ | ❌ |
+| CMS Management | ✅ | ❌ | ❌ |
+| Profile | ✅ | ✅ | ✅ |
+
+A) Filter sidebar items client-side based on `user.role` from AuthContext (recommended — clean UX; backend remains authoritative for access control)
+B) Show all items to all roles, grey out inaccessible ones
+C) Show all items, let the route guard handle the redirect on click
+
+[Answer]: