feat(web): tane.comunes.org landing + localized app screenshots

- Hugo site (site/): EN/ES intro + legal (generated from docs/legal), an
  ES/EN About page from docs/{que-es-tane,what-is-tane}.md, seed-green theme,
  responsive header, store-badge placeholders, multi-stage Hugo->nginx image.
- Golden screenshot harness (test/screenshots/): en,es,fr,de,pt,ja + RTL demo,
  real fonts via DejaVu Sans + FontManifest; skip-by-default tag so CI stays
  green. collect_screenshots.sh feeds site/ and fastlane phoneScreenshots.
- Drop editorial notes from the public explainer.

site/layouts/partials/footer.html

@@ -0,0 +1,16 @@
+<footer class="site-footer">
+  <div class="foot-inner">
+    <nav class="foot-legal">
+      {{ range (where .Site.Pages "Section" "legal") }}
+        {{ if .IsPage }}<a href="{{ .RelPermalink }}">{{ .Title }}</a>{{ end }}
+      {{ end }}
+    </nav>
+    <p class="foot-note">{{ T "footerFreeSoftware" }}</p>
+    <p class="foot-note">
+      {{ T "footerPublishedBy" }}
+      <a href="{{ .Site.Params.publisherURL }}">{{ .Site.Params.publisher }}</a>
+      · {{ T "footerContact" }}:
+      <a href="mailto:{{ .Site.Params.email }}">{{ .Site.Params.email }}</a>
+    </p>
+  </div>
+</footer>

site/layouts/partials/head.html

@@ -0,0 +1,16 @@
+<meta charset="utf-8" />
+<meta name="viewport" content="width=device-width, initial-scale=1" />
+<title>{{ .Title }} · {{ .Site.Title }}</title>
+<meta name="description" content="{{ with .Description }}{{ . }}{{ else }}{{ .Site.Params.description }}{{ end }}" />
+<meta name="theme-color" content="#2F7D34" />
+<link rel="icon" href="/favicon.png" type="image/png" />
+<link rel="apple-touch-icon" href="/apple-touch-icon.png" />
+{{ range .AllTranslations }}
+<link rel="alternate" hreflang="{{ .Language.LanguageCode }}" href="{{ .Permalink }}" />
+{{ end }}
+<meta property="og:title" content="{{ .Title }}" />
+<meta property="og:description" content="{{ with .Description }}{{ . }}{{ else }}{{ .Site.Params.description }}{{ end }}" />
+<meta property="og:type" content="website" />
+<meta property="og:image" content="/apple-touch-icon.png" />
+{{ $css := resources.Get "css/main.css" | minify | fingerprint }}
+<style>{{ $css.Content | safeCSS }}</style>

site/layouts/partials/header.html

@@ -0,0 +1,11 @@
+<header class="site-header">
+  <a class="brand" href="{{ "/" | relLangURL }}">
+    <img src="/logo.png" alt="Tane" width="36" height="36" />
+    <span>Tane</span>
+  </a>
+  <nav class="site-nav">
+    {{ with .Site.GetPage "/about" }}<a href="{{ .RelPermalink }}">{{ T "navAbout" }}</a>{{ end }}
+    <a href="{{ "/legal/" | relLangURL }}">{{ T "navLegal" }}</a>
+    {{ partial "lang-switch.html" . }}
+  </nav>
+</header>

site/layouts/partials/lang-switch.html

@@ -0,0 +1,16 @@
+{{- /* Links to this page in the other language; falls back to that language's home. */ -}}
+<span class="lang-switch">
+  {{- range .Site.Languages -}}
+    {{- $lang := . -}}
+    {{- if eq $lang.Lang $.Site.Language.Lang -}}
+      <span class="lang current" aria-current="true">{{ $lang.LanguageName }}</span>
+    {{- else -}}
+      {{- $target := "" -}}
+      {{- range $.AllTranslations -}}
+        {{- if eq .Language.Lang $lang.Lang -}}{{- $target = .RelPermalink -}}{{- end -}}
+      {{- end -}}
+      {{- if not $target -}}{{- $target = ($lang.Lang | printf "/%s/" | relURL) -}}{{- end -}}
+      <a class="lang" href="{{ $target }}" lang="{{ $lang.LanguageCode }}">{{ $lang.LanguageName }}</a>
+    {{- end -}}
+  {{- end -}}
+</span>

site/layouts/partials/store-badges.html

@@ -0,0 +1,12 @@
+{{- /* Renders store links only when configured, so nothing broken shows pre-launch. */ -}}
+<div class="store-badges">
+  {{- with .Site.Params.playStoreURL -}}
+  <a class="badge" href="{{ . }}">Google Play</a>
+  {{- end -}}
+  {{- with .Site.Params.fdroidURL -}}
+  <a class="badge" href="{{ . }}">F-Droid</a>
+  {{- end -}}
+  {{- if and (not .Site.Params.playStoreURL) (not .Site.Params.fdroidURL) -}}
+  <p class="coming-soon">{{ T "getItComingSoon" }}</p>
+  {{- end -}}
+</div>