Add remaining multi-repo files from bd-307

cmd/bd/init.go

@@ -596,6 +596,14 @@ func createConfigYaml(beadsDir string, noDbMode bool) error {
 # Debounce interval for auto-flush (can also use BEADS_FLUSH_DEBOUNCE)
 # flush-debounce: "5s"
 
+# Multi-repo configuration (experimental - bd-307)
+# Allows hydrating from multiple repositories and routing writes to the correct JSONL
+# repos:
+#   primary: "."  # Primary repo (where this database lives)
+#   additional:   # Additional repos to hydrate from (read-only)
+#     - ~/beads-planning  # Personal planning repo
+#     - ~/work-planning   # Work planning repo
+
 # Integration settings (access with 'bd config get/set')
 # These are stored in the database, not in this file:
 # - jira.url