Auto-discover repo skills/commands in spinner tips

Feature Request

Problem

The spinnerTipsOverride setting only accepts a static list of strings. In large repositories with many custom skills (e.g., 100+ skills in .claude/skills/), manually maintaining a tip list is impractical and gets stale as skills are added/removed.

Proposed Solution

Auto-discover skills from .claude/skills/ (and user-level skills) and dynamically include them in spinner tips. Each skill's SKILL.md frontmatter already has name and description — these could be used to generate tips like:

Use /create-pr to submit code for review

Suggested Behavior

• When spinnerTipsEnabled: true, automatically include discovered skills/commands alongside built-in tips
• A new setting like spinnerTipsAutoDiscover: true could control this behavior
• excludeDefault and manual tips entries should still work alongside auto-discovered ones
• Tips could be generated from skill frontmatter: Use /<skill-name> to <description>

Why This Matters

Repositories with many team-specific skills benefit from passive discoverability — developers learn about available workflows just by using Claude Code, without needing to run / and scroll through the menu. This is especially valuable for onboarding new team members.

Current Workaround

Script that scans .claude/skills/ for SKILL.md files and writes entries into settings.json, but this requires manual re-running when skills change.