feat: multi-skill install with interactive selection, --list, and --skill flags

[sametcelikbicak]

Summary

Changes rolecraft install to support multi-skill repositories like mattpocock/skills which contain multiple SKILL.md files.

Changes

src/utils/resolver.js

• enrichSkill() — new helper: reads all files in a skill directory, computes hash
• scanForSkill() — now checks container directories first (skills/, .agents/skills/, etc.) for flat and catalog layouts, deduplicates against recursive scan
• All internal resolvers return { skills: [...], sourcePath, sourceType } — all skills, not just found[0]
• resolveSkills(source) — NEW: returns array of all skills from a source

src/commands/install.js

• Uses resolveSkills instead of resolveSource
• --list — list available skills without installing
• --skill <names> — install specific skills by name (comma-separated)
• Multi-skill interactive selection — when >1 skill found, shows numbered list
• --yes with multi-skill skips selection, installs all

bin/rolecraft.js

• Parses new --list and --skill flags

Tests

• 721 tests pass (was 678), 0 failures
• New tests for resolveSkills, --list, --skill, multi-skill --yes

Docs

• Updated docs/commands/install.md with multi-skill docs, --list output example, interactive selection example

Backward Compatibility

Single-skill repositories (99% of use cases) work exactly as before. No breaking changes.