Summary

Fix Discord's flat /skill autocomplete path so it no longer inherits the old category-group cap.

Previously, the Discord adapter switched to a flat autocomplete-based /skill command, but still populated it through the legacy category collector. That meant skills could still be silently hidden once the catalog exceeded the old 25 groups × 25 skills shape. Long skill names also risked losing their original cmd_key binding after name clamping.

What changed

• added discord_skill_autocomplete_entries() for the flat Discord /skill UI
• updated the Discord adapter to use the flat collector directly
• preserved cmd_key when clamping long skill names via _clamp_command_triples()
• added regression coverage for:
  • long-name clamp preserving dispatchability
  • flat autocomplete no longer enforcing the legacy same-category cap

Why this is correct

The flat /skill command uses Discord autocomplete rather than registered subcommand groups, so it should not be constrained by the old grouped-command structural limits. This change keeps the existing filtering rules (disabled skills, hub exclusion, reserved-name handling, name clamping) while removing the obsolete cap from the autocomplete path.

Testing

• tests/hermes_cli/test_commands.py — 110 passed
• tests/gateway/test_discord_slash_commands.py — 30 passed