fix(autocomplete): filter out hidden commands when args is empty

[Adityakk9031]

Summary

In \internal/autocomplete/autocomplete.go\ (\getAllPossibleCompletions), when \len(args) == 0\ (e.g. when typing \context-dev \ and pressing TAB), the code iterated through all
oot.Commands\ without checking \child.Hidden.

This leaked internal and maintenance commands (such as __complete\ and @completion) into user-facing shell autocompletions.

Solution

Added \if !child.Hidden\ check when \len(args) == 0, matching the behavior in the non-empty args path.

Tests

• Updated \TestGetCompletions_HiddenCommand\ in \internal/autocomplete/autocomplete_test.go\ to verify that hidden commands are excluded both when a prefix is provided and when \�rgs\ is empty.