ci: give the release gate the budget headroom every nightly step already has

The push-path release gate (mp_rolling_upgrade_no_loss_no_stall) ran with the
compiled-in defaults of 60s boot / 30s convergence
(tidal-server/tests/support/multiproc.rs:54,62), which are tuned for a developer
machine. It spawns three real OS processes, drives a graceful SIGTERM ->
version-tagged restart -> heal cycle, then waits for three-way feed parity to 1e-6
over loopback gRPC.

Measured today: at the default budget it times out on "WAL relay alone must
reconverge all three nodes to 1e-6 after the rolling upgrade". With
TIDAL_TEST_BOOT_BUDGET_SECS=300 / TIDAL_TEST_CONVERGENCE_BUDGET_SECS=180 it passes
in 21s. So convergence is fast; the default simply leaves no slack. Reproduced
identically on a pre-change baseline (53c345e) in a separate worktree, so this is
budget sensitivity, not a regression from the vector-search or e2e work.

This was the only push-path step without headroom, while every nightly step already
sets it with the comment "Boot / convergence budgets are raised for a shared CI
runner" - and this is the step whose failure BLOCKS the Kaniko image build, so its
flake cost is the highest in the file.

Budgets are overrides, not weakened assertions: the test still demands exact
three-way parity to 1e-6 with no reconcile, and still fails if convergence stalls.

.woodpecker.yaml

@@ -28,6 +28,24 @@ steps:
     image: rust:1-bookworm
     when:
       event: push
+    # Budget headroom, matching the nightly steps below. The defaults are 60s boot
+    # / 30s convergence (support/multiproc.rs:54,62), tuned for a developer
+    # machine; this step spawns three real OS processes, drives a graceful
+    # SIGTERM → version-tagged restart → heal cycle, and then waits for three-way
+    # feed parity to 1e-6 over loopback gRPC.
+    #
+    # Measured 2026-08-30: at the default budget this test times out on
+    # "WAL relay alone must reconverge all three nodes to 1e-6" on a loaded
+    # machine, and passes in 21s with the raised budget — the convergence itself
+    # is fast, the default just leaves no slack. It reproduced identically on a
+    # pre-change baseline, so it is budget sensitivity and not a regression.
+    #
+    # This was the ONLY push-path step without headroom, while every nightly step
+    # already sets it "for a shared CI runner" — and this is the step that BLOCKS
+    # the image build, so its flake cost is the highest of any step in the file.
+    environment:
+      TIDAL_TEST_BOOT_BUDGET_SECS: "300"
+      TIDAL_TEST_CONVERGENCE_BUDGET_SECS: "180"
     commands:
       - apt-get update && apt-get install -y --no-install-recommends protobuf-compiler cmake clang
       - cargo test -p tidal-server --features cluster-e2e --test cluster_lifecycle