pi-synthetic v0.29.1

8b01365: Sync the static model catalog with the Synthetic API: add infinite:small:vision (vision-capable tier routing to DeepSeek-V4.1-Flash with 524K context and zero per-token pricing; reasoning efforts none/low/high/xhigh/max map by identity), and update syn:small:vision for its new DeepSeek-V4.1-Flash backend (context doubled to 524K, pricing moved to the DeepSeek tier, reasoning efforts remapped by identity).