Move GLM 5.2 to 5.3

GLM 5.3 supersedes 5.2, so every reference to the older id follows it: the zai
preset's opus, sonnet and fable tiers, and the fable tier of `default`, which
routes to the same model through OpenRouter.

Also the hardcoded Z.AI entries in both builds' model pickers, which are the one
place a model id is not read from a preset - leaving those would have gone on
offering a superseded model from the menu while the presets used the new one.

haiku stays on glm-4.7: that is the fast/cheap tier, not a 5.x.

presets/default.json

@@ -10,7 +10,7 @@
     "opus": "deepseek/deepseek-v4-flash-0731",
     "sonnet": "qwen/qwen3.7-flash",
     "haiku": "openrouter/free",
-    "fable": "z-ai/glm-5.2"
+    "fable": "z-ai/glm-5.3"
   },
   "subagentModel": "inherit",
   "gatewayModelDiscovery": true,