Enhance API with OIDC support, including login and callback endpoints. Update environment variables for OIDC configuration in .env.example. Add new features to the catalog service for listing software families, Minecraft versions, and deployment regions. Implement server management actions such as kill, delete, and update in the servers module. Integrate feature flags for maintenance mode in server operations. Update pnpm-lock.yaml with new dependencies and versions.

docs/integrations/whmcs/configurable-options.md

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+# WHMCS configurable options
+
+Map WHMCS configurable options to GameCloud server parameters at provision and upgrade time.
+
+## Overview
+
+Configurable options let customers choose RAM tiers, Minecraft versions, or software types at order time. The server module reads selected options during `CreateAccount` and `ChangePackage`.
+
+**Preferred approach:** Use addon product mappings for plan slugs; use configurable options for customer-visible upgrades that WHMCS invoices.
+
+## Standard option layout
+
+| Option name | Type | Maps to |
+|-------------|------|---------|
+| Plan | Dropdown | GameCloud plan slug (via mapping resolver) |
+| Minecraft Version | Dropdown | `minecraftVersion` |
+| Software | Dropdown | `softwareFamily` |
+| Extra Backup Slot | Quantity | WHMCS addon product — see [addons](addons.md) |
+
+Option order matters if using fallback config option indices in legacy setups. Mappings table overrides text fields when an active row exists.
+
+## Dropdown values
+
+### Software family
+
+Values must match GameCloud enum exactly:
+
+`VANILLA`, `PAPER`, `PURPUR`, `FABRIC`, `FORGE`, `NEOFORGE`, `QUILT`
+
+### Minecraft version
+
+Use semver strings present in GameCloud catalog. Invalid versions fail provisioning with module log error.
+
+## Upgrade path
+
+When a customer upgrades via WHMCS configurable option change:
+
+1. WHMCS invokes `ChangePackage`
+2. Module sends new `planSlug` to GameCloud
+3. GameCloud resizes limits; may require server restart
+
+Communicate restart requirement in WHMCS product description.
+
+## Validation
+
+The addon **Mappings** page validates plan slugs before save. Configurable option text is **not** validated until order time — typos cause provisioning failures.
+
+## Pricing
+
+WHMCS handles all pricing. GameCloud never stores invoice amounts in WHMCS mode (`BILLING_PROVIDER=whmcs`).
+
+## Example: RAM upgrade option
+
+1. WHMCS configurable option group "Upgrades"
+2. Option "RAM Tier" with values mapping to plan slugs `starter`, `pro`, `enterprise`
+3. Product mapping links WHMCS product + option combination to slug via `ProductMapping.php` resolver
+
+For complex matrices, use separate WHMCS products instead of many conditional options.
+
+## Related
+
+- [Products](products.md)
+- [Product mappings](../product-mappings.md)
+- [Troubleshooting](troubleshooting.md)