Add transparent portrait avatars for market digital employees (#202)

The catalog previously showed opaque icons or text fallbacks for the
seven digital employees, and source-pointer installs could still get
different avatars. This updates every catalog card to a 512×512
transparent portrait, bumps the listed releases, and pins the six source
repositories to commits that include the matching AgentFS avatar.

Validation: `validate_catalog_metadata.py --require-complete` (0
errors), `validate-i18n.py` (0 errors), and `translate.py --check`. All
seven WebP files have an alpha channel with fully transparent pixels and
are below 50 KB each.

agents/mimo-model-quota-monitor/entry.json

@@ -19,7 +19,7 @@
       "shortDesc": "Checks the Token Plan quota on the Xiaomi MiMo open platform on a schedule — total, used, remaining and reset time — and notifies you once when quota runs low, consumption spikes or the login expires. Read-only, never spends money or changes settings; requires a MiMo account saved in the DesireCore account store and a one-time SMS verification that you complete yourself."
     }
   },
-  "latestVersion": "1.0.0",
+  "latestVersion": "1.0.1",
   "maintainer": {
     "name": "DesireCore Official",
     "verified": true
@@ -29,13 +29,16 @@
   "redistribution": "source-pointer-only",
   "avatar": {
     "t": "M",
-    "bg": "linear-gradient(135deg, #34C759, #007AFF)"
+    "bg": "linear-gradient(135deg, #34C759, #007AFF)",
+    "image": {
+      "path": "assets/avatar.webp"
+    }
   },
   "source": {
     "kind": "git",
     "repoUrl": "https://github.com/desirecore-agent/mimo-model-quota-monitor.git",
     "repoBranch": "main",
-    "ref": "911c0a226346a8157f07d5218207f16e32ea82e0"
+    "ref": "0abbfc28f4fe3fffd6da0708a361a9c0a1fe15b9"
   },
   "requiredClientVersion": "10.0.156"
 }