visuals: print styles for the wall and the diagrams, and Phase 7 notes

- Diagrams carry a print style block, so they print as ink on white rather than
  as dark panels; the client wall and the chips go white with a hairline.
- docs/phase-7-notes.md records what batch 1 shipped, how to add a mark or an
  image, and the Lighthouse measurements taken after the batch (100/100/100/100,
  CLS 0, mobile and desktop).

(cherry picked from commit ae9282e5f62b8c7ee149ebf96f8d3f00067a49e2)

content/assets/diagrams/homelab-topology.svg

@@ -2,6 +2,19 @@
   <title id="topoTitle">Homelab topology: build host, runtime host and public edge</title>
   <desc id="topoDesc">Three hosts. The build host produces a release; the runtime host runs the site, the vector store, a workflow worker and the model gateway, all bound to loopback; the public edge terminates TLS and is the only host reachable from the internet. All three join one private mesh, and backups run in three tiers.</desc>
 
+  <style>
+    /* On paper the diagram is ink on white, not a dark panel. Presentation
+       attributes are the weakest source, so these rules win without editing
+       the drawing. */
+    @media print {
+      rect { fill: #fff; }
+      text { fill: #111; }
+      text[fill="#6ee7c6"] { fill: #0b5c48; }
+      text[fill="#8b98a8"] { fill: #444; }
+      line, path { stroke: #555; }
+      marker path { fill: #555; }
+    }
+  </style>
   <defs>
     <marker id="arrow" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
       <path d="M0 0 10 5 0 10z" fill="#6ee7c6"/>