P1 fondation : tokens layerés, reset, thèmes (base/renovation/aep/tmip), 9 primitives Astro, pont Tailwind 4, démo kitchen sink

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

components/Section.astro

@@ -0,0 +1,40 @@
+---
+/**
+ * Section — rythme vertical cohérent entre blocs de page.
+ *
+ * Props :
+ *  - alt   (boolean, false) : fond alterné (--bg-alt) pour rythmer la page
+ *  - size  ('base' | 'lg', 'base') : padding vertical --space-2xl ou --space-3xl
+ *  - id    (string) : ancre
+ *  - class (string) : classes additionnelles
+ */
+interface Props {
+  alt?: boolean;
+  size?: "base" | "lg";
+  id?: string;
+  class?: string;
+}
+
+const { alt = false, size = "base", id, class: className } = Astro.props;
+---
+
+<section
+  class:list={["tf-section", { "tf-section--alt": alt, "tf-section--lg": size === "lg" }, className]}
+  id={id}
+>
+  <slot />
+</section>
+
+<style>
+  .tf-section {
+    padding-block: var(--space-2xl);
+  }
+
+  .tf-section--lg {
+    padding-block: var(--space-3xl);
+  }
+
+  .tf-section--alt {
+    background: var(--bg-alt);
+  }
+</style>