[BUG] Desktop app: typing a slash command for a user-level skill (~/.claude/skills) does nothing, while the Skill tool loads the same skill fine

Description

User-level skills under ~/.claude/skills/ (≈45 skills, each a directory with a valid SKILL.md frontmatter containing name + description) cannot be invoked by typing their slash command in the Claude Code desktop app. Typing e.g. /grill-me and submitting does nothing — no skill loads, no error is shown.

The same skills load perfectly when the model invokes them programmatically via the Skill tool in the same environment, so skill discovery and the files themselves are fine — only the typed slash-command path is broken.

Environment

• Claude Code CLI: 2.1.235
• macOS (Darwin 25.5.0)
• Skills location: ~/.claude/skills/<skill-name>/SKILL.md
• Possibly relevant: many of the skills have Hebrew (RTL, non-ASCII) description fields; name fields are ASCII kebab-case.

Steps to reproduce

1. Create a skill at ~/.claude/skills/grill-me/SKILL.md with valid frontmatter.
2. Open the desktop app, type /grill-me and submit.
3. Nothing happens.
4. Ask Claude in words to use the skill → it invokes it via the Skill tool successfully.

Notes

This looks like the same bug as #36031 ("User-level skills from ~/.claude/skills/ appear in Desktop Code tab autocomplete but don't invoke"), which was auto-closed as stale (not planned) without a fix. Filing a new issue as instructed by the auto-close bot, since the behavior still reproduces on a current version.