feat(ui): project readme, language bars, and per-card language summary

ProjectPage fetches README (raw markdown) and language breakdown from
GitHub/Gitea REST APIs, rendering the readme as markdown and languages
as a colored proportional bar with labels.

Dashboard cards lazily fetch top 3 languages per repo and display them
inline. Language color map covers common languages.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/App.css

@@ -97,6 +97,62 @@ a.hot-pink {
   font-size: 0.7rem;
 }
 
+.project-card h5,
+.project-card .text-muted,
+.project-card span {
+  color: #ecf0f1;
+}
+
+.language-bar {
+  display: flex;
+  height: 6px;
+  border-radius: 3px;
+  overflow: hidden;
+}
+
+.language-bar-segment {
+  min-width: 2px;
+}
+
+.language-dot {
+  display: inline-block;
+  width: 8px;
+  height: 8px;
+  border-radius: 50%;
+  margin-right: 4px;
+}
+
+.project-readme {
+  background: rgba(255, 255, 255, 0.05);
+  border: 1px solid rgba(255, 255, 255, 0.1);
+  border-radius: 6px;
+  padding: 1.5rem;
+  font-size: 0.85rem;
+  line-height: 1.5;
+}
+
+.project-readme h1,
+.project-readme h2,
+.project-readme h3 {
+  font-size: 1.1rem;
+  margin-top: 1rem;
+}
+
+.project-readme pre {
+  background: rgba(0, 0, 0, 0.2);
+  padding: 0.75rem;
+  border-radius: 4px;
+  overflow-x: auto;
+}
+
+.project-readme code {
+  font-size: 0.8rem;
+}
+
+.project-readme img {
+  max-width: 100%;
+}
+
 .site-footer {
   margin-top: 3rem;
   padding: 1rem 0;