docs: add ROADMAP.md

ROADMAP.md

@@ -0,0 +1,27 @@
+# Roadmap
+
+Open ideas for the playground frontend. Tick a box when done.
+
+## Quick wins
+
+- [ ] **Labyrinth grid size crash**: `labyrinth.component.html` still binds `[gridRows]`; typed sizes above the max crash the page. Same fix as pathfinding (clamp in code, drop the binding).
+- [ ] **Lighthouse gate**: add an `assert` block to `lighthouserc.json` (e.g. performance, accessibility, SEO >= 0.9). Today CI runs the audit but never fails.
+  Note: the `@lhci/cli` → lighthouse 13 override in `package.json` is only safe without `assert`. Check it again before you add one.
+- [ ] **robots.txt + sitemap.xml**: static files in `public/`, listing all routes from `app.routes.ts`.
+- [ ] **SEO per algorithm page**: all algorithm routes use `data: { seo: 'ALGORITHMS' }`. Give each one its own key and add `SEO.<KEY>.TITLE` / `DESCRIPTION` to `en.json` and `de.json`.
+- [ ] **nginx security headers + gzip**: no CSP, `X-Content-Type-Options`, `Referrer-Policy`, `frame-ancestors` and no `gzip` in `nginx.conf`. First check with `curl -I https://app.andreas-dahm.eu/` if the reverse proxy already sets them.
+
+## Tests
+
+- [ ] `seo.service.ts`: spec for title/meta update on route change and language change.
+- [ ] Pure logic without specs: `pathfinding-animator.ts`, cloth and pendulum GPU strategies (the math around them, not the shaders), `fractal3d`.
+
+## Features
+
+- [ ] **Shareable demo state**: keep demo settings in query params (fractal zoom/center, sorting algorithm, seeds). Opening the link restores the view.
+- [ ] **New algorithm demos** (pattern: route + `RouterConstants` + `AlgorithmsService` entry + i18n + information panel):
+  - [ ] Boids / flocking (GPU path like cloth)
+  - [ ] Voronoi / Delaunay
+  - [x] A* vs Dijkstra side by side (reuse pathfinding)
+  - [ ] Fourier epicycles
+  - [ ] Reaction-diffusion (Gray-Scott) shader (reuse the fractal shader setup)