docs: clarify bulk execution and startup checks in help

manage.sh

@@ -96,13 +96,20 @@ Stage configuration:
   after [--parallel N] STACK...    Add a late stage
   exclude STACK...                 Exclude stacks from bulk operations
 
-  Each before/after declaration is one ordered stage; unlisted stacks form
+Bulk execution (without STACK):
-  the default stage. Lifecycle commands run before -> default -> after,
+  Each before/after declaration creates a stage, in declaration order.
-  reversed for stop/down. A failed stage skips all remaining stages.
+  Unlisted stacks form the default stage; excluded stacks are skipped.
-  up/start/update wait for running/healthy services when waiting is enabled.
+  up/start/restart/pull/update run before -> default -> after.
-  Services need healthchecks to verify readiness beyond the running state.
+  stop/down reverse the full stage order.
-  up/update validate every selected Compose configuration before making changes.
+  Stages run one at a time. Stacks within a stage run in parallel, limited
-  Numeric settings do not accept leading zeros.
+  by max_parallel or that stage's --parallel setting.
+  A stage finishes all its stacks; any failure skips the remaining stages.
+
+Startup checks:
+  up/update validate all selected Compose configurations before making changes.
+  up/start/update wait up to wait_timeout seconds for each stack to be ready.
+  Services with healthchecks must be healthy; other services must be running.
+  Set wait_timeout to 0 to disable waiting.
 
 Config: $CONFIG_FILE
 EOF