feat: Add sponsor page and update navigation links for sponsorship

sponsor_script.js

@@ -0,0 +1,72 @@
+document.addEventListener('DOMContentLoaded', () => {
+    fetchSponsorsData();
+});
+
+async function fetchSponsorsData() {
+    try {
+        const response = await fetch('sponsors.txt');
+        if (!response.ok) {
+            throw new Error('Failed to fetch sponsors.txt');
+        }
+        const text = await response.text();
+        const lines = text.trim().split('\n');
+        
+        const sponsors = [];
+        const userTotals = {};
+        let grandTotal = 0;
+
+        lines.forEach(line => {
+            const parts = line.split(',');
+            if (parts.length >= 3) {
+                const name = parts[0].trim();
+                const project = parts[1].trim();
+                const amountStr = parts[2].trim().replace('￥', '');
+                const amount = parseFloat(amountStr);
+                const date = parts[3] ? parts[3].trim() : '';
+
+                if (!isNaN(amount)) {
+                    sponsors.push({ name, project, amount, date });
+                    grandTotal += amount; 
+
+                    if (userTotals[name]) {
+                        userTotals[name] += amount;
+                    } else {
+                        userTotals[name] = amount;
+                    }
+                }
+            }
+        });
+
+        // Update Total
+        const totalDisplay = document.getElementById('total-amount-display');
+        if (totalDisplay) {
+            totalDisplay.innerText = `累计获得赞助: ¥${grandTotal.toFixed(2)}`;
+        }
+
+        // Recent Donations Logic
+        // Original list is chronological (oldest to newest), reverse it for newest first
+        const recentSponsors = [...sponsors].reverse();
+        renderDonationGrid(recentSponsors);
+
+    } catch (error) {
+        console.error('Error loading sponsors:', error);
+        const grid = document.getElementById('donation-list');
+        if(grid) grid.innerHTML = '<p>加载数据失败</p>';
+    }
+}
+
+function renderDonationGrid(sponsors) {
+    const container = document.getElementById('donation-list');
+    if (!container) return;
+
+    container.innerHTML = sponsors.map(s => `
+        <div class="donation-card">
+            <div class="donation-header">
+                <span class="donor-name">${s.name}</span>
+                <span class="donation-amount">¥${s.amount.toFixed(2)}</span>
+            </div>
+            <div class="donation-purpose">${s.project}</div>
+            <div class="donation-date">${s.date}</div>
+        </div>
+    `).join('');
+}