Language selector: move it into the visible top bar on every page that loads lang.js

The EN | DE | ES switcher existed but rendered into the footer slot, so a
visitor had to scroll to the bottom of the page to find it (measured live:
y=5582 on /, y=5498 on /odoo-erp-automation-bootcamp/). The user asked for a
selector a visitor can actually see.

- index.html, de/index.html, es/index.html: the slot is now the first child of
  .hero .container, right-aligned in flow above the kicker. In flow, not a
  fixed pill, so it cannot collide with the absolute .hero-notice.
- odoo-erp-automation-bootcamp/index.html: the slot is now the last child of
  .bc-topbar .container, right of the nav links, behind a hairline brass
  divider; .bc-topbar-links gets margin-left:auto so the brand stays left.
- One [data-lang-switcher] per page; the footer slot is removed everywhere.
- Styling follows the CI: Inter 12px / .06em / uppercase codes (the existing
  .lang-switch rules), active language in --brass on these midnight surfaces,
  the other two in the surrounding text colour. CSS-only, in each page's
  inline <style>; lang.js is untouched, so its redirect behaviour is unchanged.
- The rules are recorded in work/i18n/I18N-BUILD-PLAN.md §3 for the phase-2
  pages (de|es/odoo-hosting-2027.html, de|es/support.html).

de/index.html

@@ -116,6 +116,12 @@
       .hero::after{content:'';position:absolute;inset:0;background:linear-gradient(135deg,var(--midnight) 50%,rgba(13,27,46,.4) 100%);opacity:.5;z-index:0}
       .hero-bg{position:absolute;inset:0;z-index:0;overflow:hidden}.hero-bg-slide{position:absolute;inset:0;background-size:cover;background-position:center;background-repeat:no-repeat;opacity:.25;filter:brightness(1.15)saturate(1.1)}
       .hero .container{position:relative;z-index:1;flex:1;display:flex;flex-direction:column;justify-content:center}
+      /* Language selector — top-right of the hero's own top area (page has no site header). CI §1/§2:
+         brass marks the active language, body colour for the other two; lang.js owns the markup. */
+      .hero .lang-switch-slot{display:flex;justify-content:flex-end;margin-bottom:1rem}
+      .hero .lang-switch{color:rgba(255,255,255,.65)}
+      .hero .lang-switch a:hover,.hero .lang-switch a:focus-visible{color:var(--brass-bright)}
+      .hero .lang-switch a[aria-current="true"]{color:var(--brass);text-decoration:underline;text-underline-offset:3px}
       .hero-kicker{font-family:Inter,sans-serif;font-size:.72rem;font-weight:600;letter-spacing:.15em;text-transform:uppercase;color:var(--brass);margin-bottom:.75rem}
       .hero h1{color:#fff;max-width:700px;margin-bottom:1rem;font-weight:400}.hero h1 span{color:var(--brass)}
       .hero-sub{font-size:1.05rem;color:rgba(255,255,255,.7);max-width:560px;line-height:1.7;margin-bottom:1.5rem}
@@ -241,6 +247,7 @@
         <button type="button" class="hero-notice-close" aria-label="Benachrichtigung schließen">&times;</button>
       </div>
       <div class="container">
+        <div data-lang-switcher class="lang-switch-slot"></div>
         <div class="hero-kicker">Vollständig verwaltetes Odoo Community Hosting</div>
         <h1>Odoo in <span>5 Minuten</span> einsatzbereit — vollständig verwaltetes Hosting</h1>
         <p class="hero-sub">Starten Sie Ihr System in Minuten — Backups laufen automatisch, Ihre Web-Adresse ist mit SSL gesichert, Module installieren wir auf Wunsch dazu. Kein Techniker nötig.</p>
@@ -663,7 +670,6 @@
         </div>
         <div class="fcopy">Copyright &copy; ODOO4projects LLC</div>
       </div>
-      <div data-lang-switcher class="lang-switch-slot"></div>
     </footer>
 
     <script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/3.12.5/gsap.min.js"></script>