run-tests: Add harness for integration tests

The `run-tests.sh` script sets up a full environment for the integration
tests.  This includes starting Meilisearch (with a master key to enable
authentication) and generating an ephemeral JWT secret.  After the tests
are run, the environment is cleaned up.

```sh
just test

just unit-tests

just integration-tests
```

Justfile

@@ -0,0 +1,9 @@
+# vim: set et :
+
+integration-tests:
+    ./run-tests.sh --test=integration
+
+unit-tests:
+    cargo test --lib
+
+test: unit-tests integration-tests

run-tests.sh

@@ -0,0 +1,66 @@
+#!/bin/sh
+# vim: set ts=4 sts=4 sw=4 et :
+
+cleanup() {
+    if [ -n "${cid}" ]; then
+        echo 'Stopping Meilisearch ...' >&2
+        podman stop "${cid}" >/dev/null
+    fi
+    unset cid
+    if [ -f "${meilisearch_key}" ]; then
+        rm "${meilisearch_key}"
+    fi
+    unset meilisearch_key
+    if [ -f "${jwt_key}" ]; then
+        rm "${jwt_key}"
+    fi
+    unset jwt_key
+    if [ -f "${ROCKET_CONFIG}" ]; then
+        rm "${ROCKET_CONFIG}"
+    fi
+    unset ROCKET_CONFIG
+}
+
+trap cleanup INT TERM QUIT EXIT
+
+echo 'Generating Meilisearch master key ...' >&2
+MEILI_MASTER_KEY=$(tr -cd 0-9A-Za-z_- < /dev/urandom | head -c 32)
+
+echo 'Starting Meilisearch ...' >&2
+cid=$(
+    export MEILI_MASTER_KEY
+    podman run --rm -d -P \
+        -e MEILI_NO_ANALYTICS=true \
+        -e MEILI_MASTER_KEY \
+        docker.io/getmeili/meilisearch:v1.13
+)
+
+port=$(podman port ${cid} 7700/tcp | cut -d: -f2)
+printf 'Waiting for Meilisearch on port %d ...' "${port}" >&2
+until curl -fs -o /dev/null 127.0.0.1:${port}; do
+    printf '.'
+    sleep 0.25
+done
+echo ' ready' >&2
+
+meilisearch_key=$(mktemp meilisearch.token.XXXXXX)
+curl -s 127.0.0.1:${port}/keys -H "Authorization: Bearer ${MEILI_MASTER_KEY}" \
+    | jq -r '.results[] | select(.name == "Default Admin API Key") | .key' \
+    > "${meilisearch_key}"
+
+echo 'Generating JWT secret key ...' >&2
+jwt_key=$(mktemp jwt.secret.XXXXXX)
+tr -cd 0-9A-Za-z_- < /dev/urandom | head -c 32 > "${jwt_key}"
+
+ROCKET_CONFIG=$(mktemp Rocket.toml.XXXXXX)
+cat > "${ROCKET_CONFIG}" <<EOF
+[test.meilisearch]
+url = "http://127.0.0.1:${port}"
+token = "${meilisearch_key}"
+
+[test.auth]
+jwt_secret = "${jwt_key}"
+EOF
+export ROCKET_PROFILE=test
+export ROCKET_CONFIG
+cargo test "$@"