Perf: pre-compile JSX, prod React, WebP assets, immutable cache

This is the big "make scrolling smooth" pass — the biggest wins live
in cold-start, not in the scroll loop itself, but a fast cold start
means GSAP starts in a non-thrashing state and stays there.

- Drop @babel/standalone (~3MB) from the page entirely. app.jsx is
  pre-compiled to app.js via deploy/build.sh; the browser loads the
  compiled bundle directly. JSX-in-browser was running babel transform
  on every page load, which is brutal on phones.
- Switch React UMD bundles from .development to .production.min:
  ~1.1MB → ~140KB, no dev-mode warnings/checks in the hot path.
- Add `defer` + `<link rel=preload as=script>` for the React/GSAP CDN
  scripts so they fetch in parallel with HTML parse, execute in order
  after DOM is ready, and don't block first paint.
- Re-encode the three 1.4–1.8MB PNG backgrounds as WebP at full size
  (~190KB total) plus a 900px-wide mobile variant (~52KB total).
  Mobile preload links use `media=` so phones never download the
  full-size variants.
- Move bg-image URLs from inline JSX styles into styles.css so the
  mobile media query can swap them in cleanly.
- nginx: long-cache versioned static assets (Cache-Control immutable,
  1 year) since URLs already carry ?v=… cache busters; keep the HTML
  itself on must-revalidate so the version pointer can update.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/build.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+# Re-compile app.jsx -> app.js so the browser can load it directly,
+# without shipping ~3MB of @babel/standalone to every visitor.
+#
+# Usage: deploy/build.sh
+# Run this before `git commit` whenever app.jsx changes.
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+ROOT="$PWD"
+
+# Use a dedicated build dir so we don't litter the repo root with
+# node_modules / package-lock.json.
+BUILD_DIR=".build"
+mkdir -p "$BUILD_DIR"
+
+if [ ! -f "$BUILD_DIR/package.json" ]; then
+  ( cd "$BUILD_DIR" && npm init -y >/dev/null \
+      && npm install --silent --no-audit --no-fund \
+         @babel/core@7 @babel/cli@7 @babel/preset-react@7 )
+fi
+
+"$BUILD_DIR/node_modules/.bin/babel" app.jsx \
+  --presets=@babel/preset-react \
+  -o app.js
+
+echo "Built app.js ($(wc -c < app.js) bytes)"

deploy/conf.d/default.conf

@@ -17,28 +17,38 @@ server {
         try_files /facere.html =404;
     }
 
+    # The HTML entrypoint must NOT cache long — it carries the
+    # ?v=… cache-busting tags that everything else relies on.
+    location = /facere.html {
+        add_header Cache-Control "public, max-age=0, must-revalidate";
+        expires off;
+    }
+
     location / {
         try_files $uri $uri/ /facere.html;
     }
 
-    # CSS/JS/JSX: short cache so future deploys are picked up promptly
+    # CSS/JS: long-cache + immutable. URLs are versioned with ?v=… so
+    # each deploy is a brand-new key; anything served here will never
+    # need to be re-fetched in a session.
     location ~* \.(?:css|js|jsx)$ {
-        expires 5m;
-        add_header Cache-Control "public, max-age=300, must-revalidate";
+        expires 1y;
+        add_header Cache-Control "public, max-age=31536000, immutable";
         types { text/css css; application/javascript js; application/javascript jsx; }
         try_files $uri =404;
     }
 
-    # Static media: long cache (filenames are stable / change when content changes)
-    location ~* \.(?:png|jpe?g|gif|webp|svg|mp4|webm|woff2?|ttf|otf|ico)$ {
-        expires 7d;
-        add_header Cache-Control "public, max-age=604800";
+    # Static media: long cache + immutable (filenames change when content does).
+    location ~* \.(?:png|jpe?g|gif|webp|avif|svg|mp4|webm|woff2?|ttf|otf|ico)$ {
+        expires 1y;
+        add_header Cache-Control "public, max-age=31536000, immutable";
         try_files $uri =404;
     }
 
     gzip on;
     gzip_types text/plain text/css application/javascript application/json image/svg+xml;
     gzip_min_length 1024;
+    gzip_vary on;
 
     access_log /var/log/nginx/facere.access.log;
     error_log  /var/log/nginx/facere.error.log;