docs: publish Preview 19 dogfood evidence

Export the reviewed allowlisted snapshot from private source commit 05928cebd01b586cf9e9d4b8c8537a7605a6068c. This records the exact candidate, bounded capacity result, stateful migration scratch requirement, authenticated batch identity proof, and immediate live acceptance evidence.

AI-Assisted: OpenAI Codex
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

scripts/capacity-campaign.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: AGPL-3.0-only
+set -euo pipefail
+root=$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)
+cd "$root"
+test "$(uname -s)" = Linux
+
+campaign_dir=$(mktemp -d)
+cleanup() { rm -rf "$campaign_dir"; }
+trap cleanup EXIT
+fixture=${OBSERVATORY_CAPACITY_FIXTURE:-}
+if test -z "$fixture"; then
+  test "$(go env GOVERSION)" = go1.26.6
+  CGO_ENABLED=0 go build -buildvcs=false -trimpath -tags observatory_capacity_fixture -o "$campaign_dir/observatory-capacity" ./internal/capacitytest
+  fixture="$campaign_dir/observatory-capacity"
+else
+  case "$fixture" in /*) ;; *) exit 2;; esac
+  test -x "$fixture"
+fi
+
+case "${OBSERVATORY_CAPACITY_MODE:-development}" in
+  development)
+    "$fixture" \
+      -sustain-rate 200 -sustain-duration 5s \
+      -burst-rate 1000 -burst-duration 2s \
+      -minimum-primary-observations 20000 -query-iterations 3
+    ;;
+  release)
+    "$fixture" \
+      -require-cgroup -expected-cpus 4 -expected-memory-bytes 8589934592
+    ;;
+  *) exit 2;;
+esac
+
+test -z "$(git status --porcelain=v1 --untracked-files=all)"