feat(maestro): exclude hidden dirs from spawn-form autocomplete (NAP-329)

docs/superpowers/specs/2026-06-15-spawn-dir-autocomplete-design.md

@@ -33,7 +33,7 @@ The daemon lists **one directory's immediate subdirectories**; the web caches
 the result per `(daemonId, dir)` and filters the trailing path segment
 client-side, re-querying only when the user crosses a `/`. Fewer round-trips,
 instant filtering, still live. Directories only (cwd / base-repo are always
-dirs); hidden dirs included (shell parity); sorted case-insensitively; capped.
+dirs); hidden dirs excluded; sorted case-insensitively; capped.
 
 ### Wire protocol (`maestro-protocol`)
 
@@ -92,7 +92,7 @@ machinery, so older peers degrade gracefully.
 
 - Protocol: serde round-trip for the four new variants + `DirListing`, and an
   unknown-variant decode (already covered generically).
-- Daemon `dirlist`: temp-dir listing (dirs-only, hidden included, sorted), `~`
+- Daemon `dirlist`: temp-dir listing (dirs-only, hidden excluded, sorted), `~`
   and relative + empty expansion, and `not_found` / `not_a_directory` codes.
 - Daemon `broker`: `forward_list_dir` round-trip + fail-fast-while-disconnected,
   mirroring the existing forward_create/kill tests.