Zero-downtime blue-green deploys behind Caddy health checks

Split the raggr service into raggr-blue (8080) and raggr-green (8081)
behind compose profiles, add a /api/health endpoint and container
healthcheck, and add scripts/deploy.sh to build the inactive color,
wait for it to become healthy, then gracefully stop the old one.
Makefile targets resolve the active color automatically.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/deploy.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+# Zero-downtime blue-green deploy.
+#
+# Builds the inactive color, starts it, waits for its healthcheck to pass,
+# then gracefully stops the old color. Caddy health-checks both ports
+# (8080 = blue, 8081 = green) and routes traffic to whichever is healthy,
+# so the swap is invisible to clients.
+#
+# Caveats:
+# - Migrations run on the new container's startup while the old one still
+#   serves, so they must be backward-compatible (additive changes only;
+#   destructive changes need a two-step deploy).
+# - During the brief overlap both containers run pull-only Obsidian sync
+#   against the shared ./obvault mount.
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+running_services=$(docker compose ps --status running --services)
+
+if echo "$running_services" | grep -qx "raggr-blue"; then
+    OLD=blue NEW=green
+elif echo "$running_services" | grep -qx "raggr-green"; then
+    OLD=green NEW=blue
+else
+    OLD="" NEW=blue
+fi
+
+echo "==> Active: ${OLD:-none} | Deploying: $NEW"
+
+echo "==> Building raggr-$NEW..."
+docker compose --profile "$NEW" build "raggr-$NEW"
+
+echo "==> Starting raggr-$NEW and waiting for healthy..."
+if ! docker compose --profile "$NEW" up -d --wait "raggr-$NEW"; then
+    echo "!! raggr-$NEW failed to become healthy${OLD:+; raggr-$OLD is still serving}" >&2
+    docker compose --profile "$NEW" logs --tail 50 "raggr-$NEW" >&2 || true
+    docker compose --profile "$NEW" stop -t 5 "raggr-$NEW" || true
+    exit 1
+fi
+
+if [ -n "$OLD" ]; then
+    echo "==> raggr-$NEW healthy; stopping raggr-$OLD (30s grace for in-flight streams)..."
+    docker compose --profile "$OLD" stop -t 30 "raggr-$OLD"
+    docker compose --profile "$OLD" rm -f "raggr-$OLD"
+fi
+
+echo "==> Deploy complete: raggr-$NEW is live"