Fix segment picker misusing removable-tag .chip/.chips styling

The new-campaign segment checkboxes reused .chip/.chips, which is
reserved codebase-wide for click-to-remove selected tags (adds a
trailing " x" and removable-tag hover styling). Give the segment
picker its own segmento-opcao/segmento-lista classes with a minimal
non-removable style instead.

public/css/app.css

@@ -459,6 +459,20 @@ button:disabled { opacity: 0.55; cursor: not-allowed; transform: none !important
 .chips .chip { cursor: pointer; }
 .chips .chip::after { content: " x"; color: var(--muted); }
 .chips .chip:hover { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--surface)); }
+.segmento-lista { display: flex; flex-wrap: wrap; gap: 7px; margin: 8px 0 12px; }
+.segmento-opcao {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  border: 1px solid var(--border);
+  background: var(--surface);
+  color: var(--ink-2);
+  border-radius: 999px;
+  padding: 5px 11px;
+  font-size: 12px;
+  font-weight: 800;
+  cursor: pointer;
+}
 .nichos-grid {
   display: grid;
   grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));