facelift: fix light-theme scrims/thumbs - :global() the data-theme overrides

Astro scopes compound selectors, so [data-theme=light] .hero__scrim inside a component style
block could never match html[data-theme] - the light theme rendered dark scrims (embossed
low-contrast copy). Wrap the theme prefix in :global() in Hero, ProjectCard and the blog index.
Light 'blueprint' hero now reads clean.

src/components/ProjectCard.astro

@@ -65,7 +65,7 @@ const dossierNo = String(index).padStart(3, "0");
     position: relative;
     border-bottom: 1px solid rgba(63, 186, 245, 0.12);
   }
-  [data-theme="light"] .dossier__thumb {
+  :global([data-theme="light"]) .dossier__thumb {
     background: var(--surface-2);
     border-bottom-color: var(--border-accent);
   }