restructure: move web app into sources/

All served files (index.html, core/, pages/, components/, vendor/,
config.json, icons.json, favicon.svg) are now under sources/.
build.sh and components.yml stay at the repo root.
build.sh updated: WEB_DIR → sources/, MANIFEST stays at SCRIPT_DIR.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: GnomeZworc <nicolas.boufidjeline@g3e.fr>

sources/core/menu.js

@@ -0,0 +1,37 @@
+// Dynamic menu loader.
+// Fetches data for groups declared with empty children in navigation.json
+// and injects them into side-nav after it is ready.
+//
+// Imported non-blocking from index.html — does not delay routing.
+// Replace MOCK_* with real api-client calls when the backend is ready.
+
+// ── Mock data ────────────────────────────────────────────────────────────────
+
+const MOCK_ACCOUNTS = [
+  { id: 'tresorerie',   name: 'Trésorerie'   },
+  { id: 'charges',      name: 'Charges'       },
+  { id: 'produits',     name: 'Produits'      },
+  { id: 'fournisseurs', name: 'Fournisseurs'  },
+]
+
+async function fetchAccounts() {
+  // TODO: replace with real call
+  // const api = document.querySelector('api-client')
+  // return await api.finance.list('/accounts')
+  await new Promise(r => setTimeout(r, 500))  // simulate network latency
+  return MOCK_ACCOUNTS
+}
+
+// ── Injection ────────────────────────────────────────────────────────────────
+
+const nav = document.querySelector('side-nav')
+if (!nav) throw new Error('menu.js: side-nav not found in DOM')
+
+await nav.ready
+
+const accounts = await fetchAccounts()
+nav.setGroupChildren('Comptes', accounts.map(a => ({
+  label: a.name,
+  href:  `#/account?id=${a.id}`,
+  icon:  'account',
+})))