feat(viewer): mode pretty print avec coloration syntaxique et numeros de ligne pour fichiers texte (#89)

frontend/style.css

@@ -2052,6 +2052,47 @@ select {
   overflow-y: auto;
 }
 
+/* --- Pretty print (mode lecture fichiers texte non-markdown) --- */
+.pretty-view {
+  display: flex;
+  background: var(--code-bg);
+  border: 1px solid var(--border);
+  border-radius: 8px;
+  overflow: hidden;
+  max-height: 78vh;
+}
+.pretty-view .pp-gutter {
+  flex: 0 0 auto;
+  display: flex;
+  flex-direction: column;
+  padding: 16px 10px 16px 14px;
+  text-align: right;
+  font-family: "JetBrains Mono", monospace;
+  font-size: 0.8rem;
+  line-height: 1.55;
+  color: var(--text-muted);
+  opacity: 0.65;
+  user-select: none;
+  background: var(--bg-secondary);
+  border-right: 1px solid var(--border);
+  overflow: hidden;
+}
+.pretty-view .pp-pre {
+  flex: 1 1 auto;
+  margin: 0 !important;
+  border: none !important;
+  border-radius: 0 !important;
+  background: transparent !important;
+  padding: 16px !important;
+  overflow: auto;
+}
+.pretty-view .pp-pre code {
+  font-family: "JetBrains Mono", monospace;
+  font-size: 0.85rem;
+  line-height: 1.55;
+  white-space: pre;
+}
+
 /* --- Markdown Rendered Content --- */
 .md-content h1,
 .md-content h2,