Initial import of LogDarioSeq baseline

Establishes version control for the personal Logseq DB fork before
starting the server-client architecture migration and domain features
described in docs/agent-guide and the approved implementation plan.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

cli/spec/commands/completion.mli

@@ -0,0 +1,12 @@
+type opts = { shell : Cli_primitive.shell option }
+type parsed = Parsed_completion of opts
+
+type action =
+  | Completion of {
+      shell : Cli_primitive.shell;
+      registry : Command_registry.t option;
+    }
+
+val generate : Cli_primitive.shell -> Command_registry.t -> string
+
+include Command_spec.S with type parsed := parsed and type action := action