Add branching intake wizard (derived steps + radio-group atom)

A second wizard demonstrating a BRANCHING flow: the visible steps are derived
from the answers by a pure `visibleSteps` function rather than stored, so
answering "buiten Nederland gewerkt? -> ja" or reporting few hours adds steps
and the progress denominator changes live. Same Elm-style store + RemoteData
patterns as the fixed wizard; answers persist to localStorage.

- intake.machine.ts: IntakeState union + Answers + visibleSteps + pure reduce (+spec)
- intake-wizard organism, intake.page, submit-intake command
- new radio-group atom (ControlValueAccessor) in shared/ui
- /intake route + dashboard link + concepts showcase section
- tighten Aantekening.type to a 'Specialisme' | 'Aantekening' union
- README + ARCHITECTURE updated

Verified live end-to-end (branches add steps 4->5->6, review, submit) with no
console errors; build, unit tests, and Storybook all green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -19,7 +19,14 @@ npm start          # app  → http://localhost:4200
 npm run storybook  # component library, organized by atomic layer
 ```
 
-Flow: **Login → Dashboard → Mijn gegevens (wijziging) → Herregistratie**.
+Flow: **Login → Dashboard → Mijn gegevens (wijziging) → Herregistratie → Intake**.
+
+> **New here:** a **branching intake questionnaire** (`/intake`) where later questions
+> appear based on earlier answers and progress survives a page reload, plus a visual
+> walkthrough of the state-management ideas. See
+> **[docs/ARCHITECTURE.md](docs/ARCHITECTURE.md)** for diagrams (atomic-design pyramid,
+> the dispatch→reduce→view loop, RemoteData states, and "why not just signals") and a
+> section on **connecting to a .NET backend**.
 
 ### See every data state (scenario toggle)
 
@@ -71,8 +78,10 @@ Change a component once and every screen that uses it updates.
 
 **2. A whole new page = composition, no new components.**
 `pages/herregistratie/herregistratie.page.ts` is a complete new flow assembled entirely
-from existing atoms/molecules/templates — zero new building blocks. That's the payoff:
-new screens cost almost nothing.
+from existing atoms/molecules/templates — zero new building blocks. The branching
+**intake wizard** went further: it needed only **one new atom** (`radio-group`) and **one
+new organism** (`intake-wizard`); the form fields, buttons, alerts, spinner and page shell
+were all reused. That's the payoff: new screens cost almost nothing.
 
 **3. Templates remove per-page boilerplate.**
 Every page used to repeat its own back-link + heading + intro markup. `page-shell`