feat(idaa): server-side Novi member verification endpoint

Proxies GET /customers/{uuid} to Novi AMS server-to-server so members'
browser IPs are no longer in the call path, eliminating false "Access
Denied" for users on hotel/conference WiFi, VPNs, and CDN-filtered nets.

- New router: GET /v3/action/idaa/novi_member/{uuid}
- Business logic in app/methods/idaa_novi_verify_methods.py
  - Redis cache (4h TTL, key: idaa:novi_member:{uuid})
  - 404 never cached (recently-joined member anti-pattern)
  - Email space→+ normalization (Novi quirk)
  - Display name: "FirstName L." format with Name field fallback
- Registered in registry.py under /v3/action/idaa tag
- 9 unit tests covering all response paths (200/404/429/503/unreachable,
  cache hit, email normalization, display name format)
- Frontend guide (Section 12) and tests/README updated with full spec
  and migration table for frontend hand-off

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

documentation/GUIDE__AE_API_V3_for_Frontend.md

@@ -638,6 +638,61 @@ const url = URL.createObjectURL(blob);
 
 ---
 
+## 12. IDAA: Server-Side Novi Member Verification
+
+Verifies a Novi AMS member UUID by proxying the Novi API call through the Aether backend. This eliminates false "Access Denied" failures for members on hotel/conference WiFi, VPNs, and Cloudflare-filtered networks — the Novi call originates from the server's IP, not the member's browser IP.
+
+- **Method:** `GET`
+- **Path:** `/v3/action/idaa/novi_member/{uuid}`
+- **Auth:** Standard V3 (`x-aether-api-key` + `x-account-id` or `?jwt=`)
+
+### Request
+
+| Parameter | Location | Required | Description |
+|---|---|---|---|
+| `uuid` | Path | Yes | Novi member UUID (from Novi AMS) |
+
+### Response on success (`200 OK`)
+
+```json
+{
+  "data": {
+    "verified": true,
+    "full_name": "Alice S.",
+    "email": "alice+member@idaa.org"
+  }
+}
+```
+
+- `full_name`: `"{FirstName} {LastName[0]}."` format. Falls back to the Novi `Name` field if first/last are absent.
+- `email`: Novi `Email` field with space → `+` normalization applied (Novi quirk — `alice member@idaa.org` → `alice+member@idaa.org`).
+
+### Error responses
+
+| Status | Meaning | Frontend action |
+|---|---|---|
+| `404` | UUID not found in Novi, or Novi returned 200 with no identity data (empty-member anti-pattern — member may have just joined) | Treat as denied / not a member |
+| `429` | Novi rate limit hit | Surface as `'rate_limited'`; advise retry |
+| `503` | Novi unreachable or Novi 5xx error | Surface as `'api_error'`; advise retry |
+
+### Migration from direct Novi call
+
+The frontend's `+layout.svelte:verify_novi_uuid()` currently calls Novi directly from the browser. Replace that `fetch()` with this endpoint. Response code mapping:
+
+| Direct Novi result | This endpoint returns | Frontend state |
+|---|---|---|
+| `200` with identity data | `200` | `verified` |
+| `200` with no identity data | `404` | `denied` |
+| `404` | `404` | `denied` |
+| `429` | `429` | `'rate_limited'` |
+| Network error / Novi 5xx | `503` | `'api_error'` |
+
+### Caching
+
+Verified results are cached in Redis (`idaa:novi_member:{uuid}`, 4-hour TTL). `404` results are **never** cached so recently-joined members are not incorrectly denied on their next attempt.
+
+---
+
 ## 11. Troubleshooting 403 Forbidden
 
 If you receive a 403 on a valid ID: