docs(keycloak-session-store): import the session-storage lab as a new project

The keycloak project ended with four open questions that design could not
settle. A two-VM lab was built to answer them by measurement, and this is
that material: 26 experiments, 125 raw command outputs, 22 browser captures.

Follows the import procedure in README.md.

  source/     the originating repository verbatim — 78 documents, 28 SVGs,
              8 manifests, plus .source-revision recording the commit
  final/      the SSOT
    document.md   729 lines written from the 29 experiment documents, not
                  concatenated: what was predicted, what was measured, and
                  where the measurement itself was wrong
    evidence/raw    125 outputs, flattened to <experiment>__<file> because
                    the originals collided (01-baseline.txt appeared three
                    times) and the audit only globs the top level
    evidence/meta   one per raw file; command and exitCode are null and the
                    README says why rather than inventing them
    evidence/browser  22 captures
    assets/       three diagrams through techviz
    .techviz/     their VizSpecs

A separate project rather than an addition to keycloak: the B-layer answers
that project's four questions, but the A, C and D layers are about cluster
failure, SSO and operations, and one document.md should hold one subject.
The four question records there can point here through 관계.

Recorded rather than papered over: only three of the 28 diagrams were
remade. The repository forbids hand-drawn SVG and forbids titles inside the
canvas; all 28 originals carry both, so converting them is redrawing, not
reformatting. They stay in source/ and the gap is written into the document.

verify-pipeline.py passes. audit-records.py reports no issues.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/keycloak-session-store/source/deploy/lab/scripts/build-and-import.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Build the API image on this workstation and import it into each lab node's
+# containerd.
+#
+# k3s does not run Docker and the lab has no registry, so images are shipped as
+# a stream: docker save -> ssh through the lab host -> k3s ctr images import.
+# Every node needs its own copy because the scheduler may place the pod anywhere.
+#
+#   ./deploy/lab/scripts/build-and-import.sh
+#   IMAGE=keycloak-pattern-api:lab NODES="kc-lab-1" ./deploy/lab/scripts/build-and-import.sh
+set -euo pipefail
+
+IMAGE="${IMAGE:-keycloak-pattern-api:lab}"
+NODES="${NODES:-kc-lab-1 kc-lab-2}"
+LAB_HOST="${LAB_HOST:-test-server}"
+CONTEXT="${CONTEXT:-backend}"
+
+repo_root="$(git rev-parse --show-toplevel)"
+cd "$repo_root"
+
+echo "==> building ${IMAGE} from ${CONTEXT}/"
+docker build -t "$IMAGE" "$CONTEXT"
+
+for node in $NODES; do
+  echo "==> importing into ${node}"
+  # Nested ssh: the workstation cannot reach the guests directly because they
+  # sit behind the lab host's libvirt NAT. The lab host's ~/.ssh/config holds
+  # the kc-lab-* aliases.
+  docker save "$IMAGE" \
+    | ssh "$LAB_HOST" "ssh ${node} 'sudo k3s ctr images import -'"
+done
+
+echo "==> verifying"
+for node in $NODES; do
+  printf '  %-10s ' "$node"
+  ssh "$LAB_HOST" "ssh ${node} 'sudo k3s ctr images ls -q'" \
+    | grep -c "$IMAGE" \
+    | xargs -I{} echo "{} match(es)"
+done
+
+echo
+echo "next: kubectl rollout restart -n header-lab deployment/echo"