feat(mindspace): add page quota grace write and local delivery guardrails.

Centralize page HTML quota checks with grace-write semantics across page
services and workspace tools, keep localhost MindSpace links clickable in
chat display, and expand Page Data/static-page skill plus local dev docs
for quota, delivery URLs, and native Aider/OpenHands tooling.

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

mindspace-space-quota.mjs

@@ -0,0 +1,110 @@
+function asQuotaNumber(value) {
+  return Number(value ?? 0);
+}
+
+export function computeUserSpaceQuotaStats(space = {}) {
+  const quotaBytes = asQuotaNumber(space.quota_bytes);
+  const usedBytes = asQuotaNumber(space.used_bytes);
+  const reservedBytes = asQuotaNumber(space.reserved_bytes);
+  const occupiedBytes = usedBytes + reservedBytes;
+  const availableBytes = quotaBytes - occupiedBytes;
+  return {
+    quotaBytes,
+    usedBytes,
+    reservedBytes,
+    occupiedBytes,
+    availableBytes,
+    isOverQuota: occupiedBytes >= quotaBytes,
+  };
+}
+
+/**
+ * Page write grace policy:
+ * - Already at/above quota: block the next page write entirely.
+ * - Below quota but insufficient headroom: allow this write (may exceed quota).
+ * - Sufficient headroom: allow normally.
+ */
+export function evaluatePageWriteQuota(space, requiredBytes) {
+  const stats = computeUserSpaceQuotaStats(space);
+  const required = Math.max(0, asQuotaNumber(requiredBytes));
+  if (stats.isOverQuota) {
+    return {
+      allowed: false,
+      grace: false,
+      stats,
+      requiredBytes: required,
+      reason: 'over_quota',
+    };
+  }
+  if (stats.availableBytes >= required) {
+    return {
+      allowed: true,
+      grace: false,
+      stats,
+      requiredBytes: required,
+      reason: 'sufficient',
+    };
+  }
+  return {
+    allowed: true,
+    grace: true,
+    stats,
+    requiredBytes: required,
+    reason: 'grace_write',
+  };
+}
+
+export function buildPageWriteQuotaError(
+  evaluation,
+  { messagePrefix = '剩余空间不足' } = {},
+) {
+  const { stats, requiredBytes, reason } = evaluation;
+  const message =
+    reason === 'over_quota'
+      ? '空间已满，请先清理后再创建或修改页面'
+      : messagePrefix;
+  return Object.assign(new Error(message), {
+    code: 'quota_exceeded',
+    details: {
+      requiredBytes,
+      availableBytes: Math.max(0, stats.availableBytes),
+      usedBytes: stats.usedBytes,
+      quotaBytes: stats.quotaBytes,
+      overQuota: reason === 'over_quota',
+      graceWrite: reason === 'grace_write',
+    },
+  });
+}
+
+export function assertPageWriteQuota(space, requiredBytes) {
+  const evaluation = evaluatePageWriteQuota(space, requiredBytes);
+  if (!evaluation.allowed) {
+    throw buildPageWriteQuotaError(evaluation);
+  }
+  return evaluation;
+}
+
+export function isMindSpacePageWriteRelativePath(relativePath) {
+  const normalized = String(relativePath ?? '').replace(/\\/g, '/').trim();
+  if (!normalized.toLowerCase().endsWith('.html')) return false;
+  const zone = normalized.split('/')[0]?.toLowerCase();
+  return zone === 'public' || zone === 'draft';
+}
+
+export async function loadUserSpaceForQuota(pool, userId) {
+  if (!pool || !userId) return null;
+  const [rows] = await pool.query(
+    `SELECT id, quota_bytes, used_bytes, reserved_bytes, status
+     FROM h5_user_spaces WHERE user_id = ? LIMIT 1`,
+    [userId],
+  );
+  return rows[0] ?? null;
+}
+
+export async function assertPageWriteQuotaForUser(pool, userId, requiredBytes) {
+  const space = await loadUserSpaceForQuota(pool, userId);
+  if (!space || space.status !== 'active') {
+    throw Object.assign(new Error('用户空间不可用'), { code: 'space_unavailable' });
+  }
+  return assertPageWriteQuota(space, requiredBytes);
+}