feat(plan-01): Phase 1 — relocate harness code to packages/casan-harness (symlink facade)

Physically move the pure-code subtrees out of .specify into the package, leaving
compat symlinks at the old .specify/<dir> paths so every existing reference (internal
CASAN_HARNESS_ROOT + external CI/docker/mjs) keeps resolving. Runtime state stays put.

Moved (git mv): scripts/ tests/ security/ templates/ config/ governance/ memory/
  .specify/<dir>  ->  packages/casan-harness/<dir>   (+ .specify/<dir> symlink)
Stays in .specify (state/governance/domain, handled later): logs/ agentops/ level5/
  init-options.json traceability-map.json

Python `.resolve()` self-location followed the compat symlink into packages and lost
the app root; generate-casan-demo-context.py, generate-agentops-dashboard.py and
dashboard-server.py now walk UP for the `.specify` state marker instead of a fixed
parent depth (fixes "missing trace files" in run-casan4).

Full gate: PASS=64 FAIL=0 SKIP=3 (CASAN_CI_STEP_TIMEOUT_SEC=1200 — track-a ~450s runs
close to the 600s default and can tip over under load; this is timing variance, not a
regression — it passed cleanly with headroom). Runtime log/audit artifacts kept unstaged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AINative_OKR_CASAN5/packages/casan-harness/tests/phase-sec19-tests.sh

@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -uo pipefail
+
+# CASAN Plan-16 SEC-19 (ARCH-05) — atomic + locked control-plane writes.
+#
+# The control-plane store did an unlocked, non-atomic load→modify→save, so two
+# concurrent `set`/`rollback` runs could lose a write or fork the audit hash chain.
+# Now the critical section holds a POSIX flock and the store is written atomically
+# (tmp + rename). Proves concurrent writes on distinct keys all survive and the
+# chain still verifies, with no torn/partial store file.
+#
+# Deterministic; hermetic (temp store + temp keys).
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+source "$SCRIPT_DIR/../scripts/bash/casan-paths.sh"
+PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+CP="$CASAN_HARNESS_ROOT/scripts/bash/control-plane-settings.py"
+WORK="$(mktemp -d)"
+trap 'rm -rf "$WORK"' EXIT
+
+export CASAN_CP_STORE_FILE="$WORK/store.json"
+export CASAN_CP_KEY_DIR="$WORK/keys"
+export CASAN_CP_PUB="$WORK/pub.pem"
+
+PASS=0; FAIL=0
+pass() { echo "PASS: $1"; PASS=$((PASS + 1)); }
+fail() { echo "FAIL: $1"; FAIL=$((FAIL + 1)); }
+
+echo "===== Plan-16 SEC-19: atomic + locked control-plane writes ====="
+
+# Fire four concurrent writers on distinct non-sensitive keys.
+python3 "$CP" set compression.enabled true      --actor a --reason r >/dev/null 2>&1 &
+python3 "$CP" set compression.mode structural    --actor a --reason r >/dev/null 2>&1 &
+python3 "$CP" set cost.absolute_cap_usd 5         --actor a --reason r >/dev/null 2>&1 &
+python3 "$CP" set model.primary "ollama:ornith"   --actor a --reason r >/dev/null 2>&1 &
+wait
+
+COUNT="$(python3 "$CP" get-all | python3 -c 'import json,sys; print(len(json.load(sys.stdin)))' 2>/dev/null)"
+[[ "$COUNT" == "4" ]] \
+  && pass "all 4 concurrent writes survived (no lost update)" \
+  || fail "lost update under concurrency (only $COUNT/4 keys present)"
+
+python3 "$CP" verify-audit >/dev/null 2>&1 \
+  && pass "audit chain intact after concurrent writes" \
+  || fail "audit chain forked/broken under concurrency"
+
+# The store must always be valid JSON (atomic rename ⇒ never torn) and no tmp left.
+python3 -c "import json; json.load(open('$CASAN_CP_STORE_FILE'))" 2>/dev/null \
+  && pass "store file is valid JSON (atomic write, not torn)" \
+  || fail "store file torn / invalid JSON"
+if ls "$WORK"/*.tmp >/dev/null 2>&1; then
+  fail "leftover .tmp file (atomic rename incomplete)"
+else
+  pass "no leftover .tmp file"
+fi
+
+echo ""
+echo "===== SEC-19 SUMMARY: PASS=$PASS FAIL=$FAIL ====="
+[[ "$FAIL" -eq 0 ]] || exit 1