Add El source files for all client-side JS

Recovers original JS from git history and ports it into proper El source
files under src/js/. Each file wraps the original JS in a native_js call
inside a main() function, making it valid El that compiles to a
self-contained IIFE via elc --target=js --bundle.

Files added:
  src/js/account-auth.el       - Supabase OTP magic-link (sendMagicLink)
  src/js/account-dashboard.el  - Account dashboard: session, plan card, family
  src/js/chat-widget.el        - Demo chat widget (neuronDemoToggle/Send/Reset)
  src/js/checkout-auth.el      - Checkout auth: OAuth, email sign-in/up
  src/js/checkout-free.el      - Free plan: auth-badge watch -> payment reveal
  src/js/checkout-stripe.el    - Stripe Payment Element (reads NEURON_CFG)
  src/js/enterprise.el         - Enterprise inquiry form + headcount filter
  src/js/environmental.el      - Efficiency calculator slider
  src/js/gallery.el            - Gallery nav, search/sort, Supabase voting
  src/js/main.el               - Share page voting + copyForPlatform
  src/js/marketplace.el        - Developer interest form
  src/js/nav.el                - Nav hamburger + Mission dropdown
  src/js/styles.el             - Landing: nav scroll, reveal, founding counter

Dockerfile.stage

@@ -62,7 +62,7 @@ RUN apt-get update \
         ca-certificates \
  && rm -rf /var/lib/apt/lists/* \
  && groupadd -r landing && useradd -r -g landing landing \
- && mkdir -p /srv/landing/assets /srv/landing/shares \
+ && mkdir -p /srv/landing/assets /srv/landing/js /srv/landing/shares \
  && mkdir -p /srv/soul/engram-demo \
  && chown -R landing:landing /srv/landing /srv/soul
 
@@ -73,6 +73,7 @@ COPY --from=builder /build/soul-demo  /usr/local/bin/soul-demo
 COPY dist/engram-snapshot.json /srv/soul/engram-demo/snapshot.json
 
 COPY src/assets /srv/landing/assets
+COPY dist/js    /srv/landing/js
 COPY src/llms.txt /srv/landing/llms.txt
 # Pre-rendered HTML shells (about, terms, enterprise-terms, index) used as
 # fallback when the El page-builder hasn't been seeded yet at startup.