docs: document server:-prefixed scopes and case-insensitive role mapping

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

HOWTO.md

@@ -170,10 +170,10 @@ Logto is proxy-aware via `TRUST_PROXY_HEADER=1`. The `LOGTO_ENDPOINT` and `LOGTO
 3. **Create API Resource**: API Resources → Create
    - Name: `Cameleer Server API`
    - Indicator: your API URL (e.g., `https://cameleer.siegeln.net/api`)
-   - Add permissions: `admin`, `operator`, `viewer`
+   - Add permissions: `server:admin`, `server:operator`, `server:viewer`
 4. **Create M2M application** (for SaaS platform): Applications → Create → Machine-to-Machine
    - Name: `Cameleer SaaS`
-   - Assign the API Resource created above with `admin` scope
+   - Assign the API Resource created above with `server:admin` scope
    - Note the **Client ID** and **Client Secret**
 5. **Configure Cameleer OIDC login**: Use the admin API (`PUT /api/v1/admin/oidc`) or set env vars for initial seeding:
    ```