fix(db): drop tp/ep/num_gpu >= 1 checks to allow aggregated multinode configs (#299)

Author: adibarra

packages/db/migrations/004_relax_decode_zero_constraints.sql

@@ -0,0 +1,17 @@
+-- ============================================================
+-- CONFIGS — allow prefill/decode tp / ep / num_gpu = 0
+-- ============================================================
+--
+-- Aggregated multinode disagg runs can produce a config with no decode
+-- workers for low-conc sweeps (e.g. conc=1 on dsv4 run 25296668638 had
+-- decode_tp=0, decode_ep=0, num_decode_gpu=0 with all 8 GPUs on prefill).
+-- The original `>= 1` checks rejected these rows during ingestion, so the
+-- conc=1 point silently disappeared from the official chart. Drop the
+-- prefill-side mirrors too for symmetry.
+
+alter table configs drop constraint configs_decode_tp_positive;
+alter table configs drop constraint configs_decode_ep_positive;
+alter table configs drop constraint configs_num_decode_gpu_positive;
+alter table configs drop constraint configs_prefill_tp_positive;
+alter table configs drop constraint configs_prefill_ep_positive;
+alter table configs drop constraint configs_num_prefill_gpu_positive;