Update Convex Docker image tags to latest release

The pinned commit hashes (00bd9272, 33cef775) are from ~Nov 2025 and
incompatible with convex npm package >=1.30, causing deploy failures
with "missing field `functions`" errors.

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

templates/compose/convex.yaml

@@ -7,7 +7,7 @@
 
 services:
   backend:
-    image: ghcr.io/get-convex/convex-backend:00bd92723422f3bff968230c94ccdeb8c1719832
+    image: ghcr.io/get-convex/convex-backend:a9a760ca10399ed42e1b4bb87c78539a235488c7
     volumes:
       - data:/convex/data
     environment:
@@ -47,7 +47,7 @@ services:
       start_period: 10s
 
   dashboard:
-    image: ghcr.io/get-convex/convex-dashboard:33cef775a8a6228cbacee4a09ac2c4073d62ed13
+    image: ghcr.io/get-convex/convex-dashboard:a9a760ca10399ed42e1b4bb87c78539a235488c7
     environment:
       - SERVICE_URL_DASHBOARD_6791
       # URL of the Convex API as accessed by the dashboard (browser).