fix: replace frontend with Rust OPAQUE API + Flutter keypad UI

- Full OPAQUE auth flow via WASM client SDK (client-wasm crate)
- New user: Key Register → Key Login → Code Register (icon selection) → done
- Existing user: Key Login → get login-data → icon keypad → Code Login → done
- Icon-based keypad matching Flutter design:
  - 2 cols portrait, 3 cols landscape
  - Key tiles with 3-col sub-grid of icons
  - Navy border press feedback
  - Dot display with backspace + submit
- SVGs rendered as-is (no color manipulation)
- SusiPage with Login/Signup tabs
- LoginKeypadPage and SignupKeypadPage for code flows
- Secret key display/copy on signup
- Unit tests for Keypad component
- WASM pkg bundled locally (no external dep)

Dockerfile

@@ -1,17 +1,18 @@
 # Stage 1: Build
 FROM oven/bun:1 AS build
 WORKDIR /app
-COPY package.json bun.lock ./
-RUN bun install --frozen-lockfile
-COPY . .
-ARG VITE_NKODE_API_URL=https://api.nkode.donovankelly.xyz
+
+ARG VITE_NKODE_API_URL
 ENV VITE_NKODE_API_URL=$VITE_NKODE_API_URL
+
+COPY package.json bun.lock* ./
+RUN bun install --frozen-lockfile || bun install
+COPY . .
 RUN bun run build
 
 # Stage 2: Serve
 FROM nginx:alpine
 COPY --from=build /app/dist /usr/share/nginx/html
-# SPA routing: all paths → index.html
 RUN printf 'server {\n  listen 80;\n  root /usr/share/nginx/html;\n  index index.html;\n  location / {\n    try_files $uri $uri/ /index.html;\n  }\n}\n' > /etc/nginx/conf.d/default.conf
 EXPOSE 80
 CMD ["nginx", "-g", "daemon off;"]