docs: remove free tier, update rate limits and auth for demo+pro model

- Remove free tier from rate limits, add Demo (5/hour, watermarked)
- Update auth section: remove free-tier key mention, link to docfast.dev
- Update getting started: demo → upgrade to Pro → use API key
- Add deprecated: true to /v1/signup/free swagger annotation
- Regenerate openapi.json

dist/services/db.js

@@ -146,6 +146,8 @@ export async function initDatabase() {
       );
       CREATE INDEX IF NOT EXISTS idx_api_keys_email ON api_keys(email);
       CREATE INDEX IF NOT EXISTS idx_api_keys_stripe ON api_keys(stripe_customer_id);
+      CREATE UNIQUE INDEX IF NOT EXISTS idx_api_keys_stripe_unique
+        ON api_keys(stripe_customer_id) WHERE stripe_customer_id IS NOT NULL;
 
       CREATE TABLE IF NOT EXISTS verifications (
         id SERIAL PRIMARY KEY,

dist/services/keys.js

@@ -60,21 +60,37 @@ export async function createFreeKey(email) {
     return entry;
 }
 export async function createProKey(email, stripeCustomerId) {
+    // Check in-memory cache first (fast path)
     const existing = keysCache.find((k) => k.stripeCustomerId === stripeCustomerId);
     if (existing) {
         existing.tier = "pro";
         await queryWithRetry("UPDATE api_keys SET tier = 'pro' WHERE key = $1", [existing.key]);
         return existing;
     }
+    // UPSERT: handles duplicate webhooks across pods via DB unique index
+    const newKey = generateKey("df_pro");
+    const now = new Date().toISOString();
+    const result = await queryWithRetry(`INSERT INTO api_keys (key, tier, email, created_at, stripe_customer_id)
+     VALUES ($1, $2, $3, $4, $5)
+     ON CONFLICT (stripe_customer_id) WHERE stripe_customer_id IS NOT NULL
+     DO UPDATE SET tier = 'pro'
+     RETURNING key, tier, email, created_at, stripe_customer_id`, [newKey, "pro", email, now, stripeCustomerId]);
+    const row = result.rows[0];
     const entry = {
-        key: generateKey("df_pro"),
-        tier: "pro",
-        email,
-        createdAt: new Date().toISOString(),
-        stripeCustomerId,
+        key: row.key,
+        tier: row.tier,
+        email: row.email,
+        createdAt: row.created_at instanceof Date ? row.created_at.toISOString() : row.created_at,
+        stripeCustomerId: row.stripe_customer_id || undefined,
     };
-    await queryWithRetry("INSERT INTO api_keys (key, tier, email, created_at, stripe_customer_id) VALUES ($1, $2, $3, $4, $5)", [entry.key, entry.tier, entry.email, entry.createdAt, entry.stripeCustomerId]);
-    keysCache.push(entry);
+    // Refresh in-memory cache
+    const cacheIdx = keysCache.findIndex((k) => k.stripeCustomerId === stripeCustomerId);
+    if (cacheIdx >= 0) {
+        keysCache[cacheIdx] = entry;
+    }
+    else {
+        keysCache.push(entry);
+    }
     return entry;
 }
 export async function downgradeByCustomer(stripeCustomerId) {
@@ -86,6 +102,20 @@ export async function downgradeByCustomer(stripeCustomerId) {
     }
     return false;
 }
+export async function findKeyByCustomerId(stripeCustomerId) {
+    // Check DB directly — survives pod restarts unlike in-memory cache
+    const result = await queryWithRetry("SELECT key, tier, email, created_at, stripe_customer_id FROM api_keys WHERE stripe_customer_id = $1 LIMIT 1", [stripeCustomerId]);
+    if (result.rows.length === 0)
+        return null;
+    const r = result.rows[0];
+    return {
+        key: r.key,
+        tier: r.tier,
+        email: r.email,
+        createdAt: r.created_at instanceof Date ? r.created_at.toISOString() : r.created_at,
+        stripeCustomerId: r.stripe_customer_id || undefined,
+    };
+}
 export function getAllKeys() {
     return [...keysCache];
 }