docs: IPv4 renews monthly, document what happens when credit runs out

apps/docs/content/company/payment.mdx

@@ -80,6 +80,17 @@ The maximum total that can be automatically charged within a single calendar mon
 </DropdownItem>
 </Dropdown>
 
+## When Credit Runs Out
+
+Resource usage is deducted from your credit hourly, while subscriptions such as the project core and a dedicated IPv4 address are charged for a month in advance and renewed on the day they were activated.
+
+If your credit cannot cover a renewal:
+
+- The renewal fails and you are notified in the dashboard.
+- A dedicated IPv4 address is released and the project falls back to the shared IPv4. The subscription is not restored automatically after a top-up; add the address again from the project's routing settings once credit is available, which starts a new paid month.
+
+Enable [automatic top-ups](#automatic-top-ups) to avoid failed renewals.
+
 ## Billing Information
 
 You are required to enter billing details for all transactions (manual and automatic top-ups), with one exception:

apps/docs/content/company/pricing.mdx

@@ -94,7 +94,7 @@ Enhance your deployment with these optional services to meet specific requiremen
   <tbody>
     <tr>
       <td className="w-fit whitespace-nowrap"><strong>Dedicated IPv4</strong></td>
-      <td className="w-fit whitespace-nowrap"><strong>$3.00</strong> per 30 days</td>
+      <td className="w-fit whitespace-nowrap"><strong>$3.00</strong> per month</td>
       <td className="w-fit">Exclusive IPv4 address for your project (instead of shared)</td>
     </tr>
     <tr>

apps/docs/content/guides/public-access.mdx

@@ -31,4 +31,4 @@ Zerops offers three public access methods: zerops.app subdomains (dev only, 50MB
 - Configurable firewall: blacklist or whitelist per port
 
 ## Gotchas
-1. **Dedicated IPv4 is non-refundable**: $3/30 days, auto-renews — the fee isn't refunded if removed early, but the address can be reused in another project until the subscription ends
+1. **Dedicated IPv4 is non-refundable**: $3/month, auto-renews — the fee isn't refunded if removed early, but the address can be reused in another project until the subscription ends. If a renewal fails for lack of credit, the address is released and must be added again after a top-up

apps/docs/content/references/networking/public-access.mdx

@@ -74,11 +74,12 @@ Before setting up domain access, you need to configure public IP addresses. Zero
 
 #### IPv4 Configuration
 
-**Dedicated IPv4 Address ($3/30 days)**
+**Dedicated IPv4 Address ($3/month)**
 - Dedicated to your project and shared across all project services
 - One IPv4 address per project limit
 - Protects against blacklisting risks associated with shared IPs
-- Subscription automatically renews every 30 days *(cannot be purchased with promo credit)*
+- Subscription automatically renews every month on the day it was activated *(cannot be purchased with promo credit)*
+- If the renewal cannot be paid, the address is released and the project falls back to the shared IPv4. Topping up does not restore it; add the address again once credit is available (see [Top-up & Billing](/company/payment#when-credit-runs-out))
 - Fee is non-refundable but address can be reused in another project until subscription ends
 - **Recommended for production workloads**