On macOS, watching deep dependency trees can exhaust file descriptors and lead to spawn EBADF failures. The skills watcher only needs to observe skill changes, so ignore dotfiles, node_modules, and dist by default. Adds regression coverage.
* fix: truncate skill command descriptions to 100 chars for Discord
Discord slash commands have a 100 character limit for descriptions.
Skill descriptions were not being truncated, causing command registration
to fail with an empty error from the Discord API.
* style: format
* style: format
