fix(skills): stop skill install . cloning into the skills dir itself

[clawedassistant26]

moshcode skill install . (run from inside the skill repo you just wrote, the most natural way to install it) targets ~/.claude/skills itself instead of a subdirectory. .. targets ~/.claude.

Cause

skillName() takes the last path segment of the source, so . and .. come back as the literal names "." and "..". skillInstallAction then builds the clone target with path.join(claudeSkillsDir(), name), which collapses them:

"."  -> ~/.claude/skills
".." -> ~/.claude

Reproduced

Ran the real install path (planSkillInstall + runSkillInstall, real git) against a throwaway HOME.

Fresh machine, ~/.claude/skills not created yet:

git args: clone --depth 1 . /tmp/home/.claude/skills
RESULT:   [{"key":"claude","status":"installed","code":0}]

~/.claude/skills/.git
~/.claude/skills/SKILL.md

The clone succeeds, the skills root becomes a checkout of that one skill, and the command reports success. Every later install lands inside that repo's working tree.

Where skills already exist, the same command fails with no explanation of why:

fatal: destination path '/tmp/home/.claude/skills' already exists and is not an empty directory.
. -> [{"key":"claude","status":"failed","code":128}]

An explicit --name . reaches the same place, since sanitize keeps dots.

Fix

src/skills.mjs only. A . / .. source is resolved against the filesystem and named after the directory it points at, so skill install . installs the repo you are standing in under its own name. As an explicit --name it falls back to skill. Nothing else changes: URLs, plain paths, trailing slashes and .git stripping all resolve exactly as before.

Tests

Two added to test/skills.test.mjs, one on the derived name and one asserting the clone destination stays a direct child of the skills dir. Verified by stashing only src/skills.mjs: both fail on current main, both pass with the fix.

Full suite: 141/141 pass (was 139).