Merge pysim-otaman-server into otaman (monorepo, v1.7.0)

- Move PWA into frontend/; server package at pysim_otaman_server/
- Server now serves the PWA (same origin -> no CORS/PNA): static file handler
  + --web-dir flag + injects window.PYSIM_EMBEDDED marker into index.html
- Frontend defaults to relative API base when embedded (pysimBase = '')
- Version 1.7.0 aligned: server.py VERSION, pyproject.toml, PWA header
- SW cache bump otaman-v7 -> otaman-v8
- Docs: combined README + docs/api.md endpoint reference; update links
- Fix stale package.json repository URL

frontend/sw.js

@@ -0,0 +1,54 @@
+const CACHE = 'otaman-v8';
+const URLS = [
+  'index.html',
+  'help.html',
+  'help-ru.html',
+  'style.css',
+  'sim.png',
+  'icon-192.png',
+  'icon-512.png',
+  'manifest.json',
+  'des-bundle.js',
+  'aes-bundle.js',
+  'sim.svg',
+  'sim_anim.svg',
+  'nosim.svg',
+];
+
+self.addEventListener('install', e => {
+  e.waitUntil(
+    caches.open(CACHE).then(c => c.addAll(URLS))
+  );
+  self.skipWaiting();
+});
+
+self.addEventListener('activate', e => {
+  e.waitUntil(
+    caches.keys().then(keys =>
+      Promise.all(keys.filter(k => k !== CACHE).map(k => caches.delete(k)))
+    ).then(() => clients.claim())
+  );
+});
+
+self.addEventListener('fetch', e => {
+  if (!e.request.url.startsWith('http')) return;
+  if (e.request.method !== 'GET') return;
+  const isNavigate = e.request.mode === 'navigate' || e.request.url.endsWith('sw.js');
+  if (isNavigate) {
+    e.respondWith(
+      fetch(e.request).then(res => {
+        const clone = res.clone();
+        caches.open(CACHE).then(c => c.put(e.request, clone));
+        return res;
+      }).catch(() => caches.match(e.request))
+    );
+  } else {
+    e.respondWith(
+      caches.match(e.request).then(r => r || fetch(e.request).then(res => {
+        const clone = res.clone();
+        caches.open(CACHE).then(c => c.put(e.request, clone));
+        return res;
+      }))
+    );
+  }
+});