🐛 [Security] Type safety and error handling in version sorting and temp file creation

Description

1. Gem::Version.new(v) rescue v in BinaryFetcher returned raw strings on invalid gem versions, causing ArgumentError (comparison of Gem::Version with String) when sorting.
2. unzip command return value was ignored during wheel extraction.
3. Temporary directory creation in LocalConnection used predictable /tmp/antigravity-ruby-#{$$} instead of Dir.mktmpdir.
4. YAML.safe_load in Skill.load raised unhandled Psych::SyntaxError instead of standard ArgumentError.

Fix

• Used Gem::Version.correct? before parsing versions.
• Checked system("unzip", ...) return code.
• Switched to Dir.mktmpdir("antigravity-ruby-").
• Rescued Psych::SyntaxError in Skill to wrap in ArgumentError.

Start by locating BinaryFetcher, LocalConnection, and Skill, then inspect the version sorting, wheel extraction, temporary directory, and YAML loading paths described in the issue. Verify that invalid versions sort safely, unzip failures are handled, temporary directories are unpredictable, and malformed YAML is exposed as ArgumentError.