Open buy buttons in CrowdRepublic crowdfunding modal.

Replace donate.stream links with a modal announcing the upcoming campaign on CrowdRepublic, with RU/EN copy and the old buy URL commented out.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/providers/CrowdfundingModal.module.css

@@ -0,0 +1,72 @@
+.overlay {
+  position: fixed;
+  inset: 0;
+  z-index: 1000;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 24px;
+  background: rgba(4, 3, 8, 0.78);
+  backdrop-filter: blur(6px);
+}
+
+.dialog {
+  width: min(100%, 480px);
+  padding: 32px 28px 28px;
+  border: 1px solid var(--color-border-strong);
+  border-radius: var(--radius-lg);
+  background: var(--color-bg-elevated);
+  box-shadow:
+    var(--shadow-glow),
+    0 24px 48px rgba(0, 0, 0, 0.45);
+}
+
+.title {
+  margin: 0 0 16px;
+  font-size: 22px;
+  font-weight: 700;
+  line-height: 1.3;
+}
+
+.message {
+  margin: 0 0 24px;
+  font-size: 16px;
+  line-height: 1.65;
+  color: var(--color-text-muted);
+}
+
+.link {
+  color: var(--color-gold-bright);
+  text-decoration: underline;
+  text-decoration-color: var(--color-gold-dim);
+  text-underline-offset: 3px;
+  word-break: break-all;
+}
+
+.link:hover {
+  color: var(--color-gold);
+}
+
+.closeBtn {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 100%;
+  padding: 12px 22px;
+  border: 1px solid var(--color-border-strong);
+  border-radius: var(--radius-md);
+  background: transparent;
+  color: var(--color-gold-bright);
+  font: inherit;
+  font-size: 15px;
+  font-weight: 600;
+  cursor: pointer;
+  transition:
+    background 0.2s ease,
+    transform 0.15s ease;
+}
+
+.closeBtn:hover {
+  background: rgba(200, 161, 102, 0.08);
+  transform: translateY(-1px);
+}