[datlechin]

Summary

• ConnectionGroupName has no length limit, so a macOS group name round-trips unchanged.
• Reading a stored group name no longer cuts it at 64 characters. Control characters still become spaces and a blank name is still refused.
• Removed ConnectionGroupName::MAX_CHARS and GroupNameError::TooLong (code group_name.too_long).
• name_rules::checked and cleaned take no limit. ConnectionTagName keeps its 32 cap by checking and cutting on its own.
• Linux New Group dialog accepts names past 64 characters.
• ADR 0006 and linux/docs/storage.md no longer state the cap.
• Linux changelog fragment 3994.changed.md.

Test plan

Tests changed on purpose because they pinned the 64 cap:

• connection_group_name: group_name_rejects_blank_long_and_control_characters is now group_name_rejects_blank_and_control_characters; the_limit_counts_characters_not_bytes is now a_name_of_any_length_is_kept_whole; a_stored_name_is_cleaned_rather_than_refused drops the cut case.
• group_name_error::each_name_error_has_a_code_of_its_own drops group_name.too_long.
• connections::a_group_an_earlier_build_wrote_past_the_limits_still_loads is now a_long_group_loads_whole_and_control_characters_are_cleaned.
• legacy_groups::a_name_too_long_or_with_control_characters_is_cleaned_first is now a_long_name_is_kept_and_control_characters_are_cleaned_first.
• name_rules::a_name_is_trimmed_and_checked_in_characters and a_stored_name_loses_control_characters_and_the_excess drop the length cases; the tag's character count moved to connection_tag_name::the_limit_counts_characters_not_bytes.
• Linux new_group_create_response_disabled_until_valid_unique_name: a 200-character name now enables Create.

Checks:

• cargo test -p tablepro-storage -p tablepro-mcp and clippy on both pass on macOS.
• The Linux app crate does not build on macOS (glycin-common), so its widget test runs in CI.