Add Phase 5 Caddy deployment config and sync script

- deploy/baflakehouse.caddy: handle_path snippet routes /baflakehouse*
  to docs/ with prefix stripping so pkgdown flat structure maps correctly
- bin/sync-caddy.sh: one-time script to install snippet and zero-downtime
  reload Caddy; deploy.R handles everything after that automatically

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

deploy/baflakehouse.caddy

@@ -0,0 +1,13 @@
+# BAF Lakehouse pkgdown site
+# Served at: https://docs.robwiederstein.org/baflakehouse
+#
+# handle_path strips the /baflakehouse prefix before handing off to the
+# file server, so requests map correctly to the flat docs/ directory.
+#
+# NOTE: The path below must match the mount point inside the Caddy Docker
+# container (i.e., wherever /data/projects/ is mounted in docker-compose.yml).
+
+handle_path /baflakehouse* {
+    root * /data/projects/bank-fraud-baf-lakehouse/docs
+    file_server
+}