pi-synthetic v0.26.3

23fae71: Sync the static model catalog with the Synthetic API: remove hf:zai-org/GLM-5.2 (no longer upstream), add hf:deepseek-ai/DeepSeek-V4.1-Flash (524K context, vision, reasoning efforts none/low/high/xhigh/max), and update syn:large:text for its new GLM-5.3-Flash backend (off disabled, low/high/max by identity).