V1.2.1 - #640

…ries

Skills found in multiple configured skills_paths directories now resolve
to a single copy. Directory paths are ordered by priority so that a skill
defined in a local project directory (e.g. ./.cecli/skills) shadows the
same-named skill in any other directory, followed by other configured
directories in the listed order, with home directories (e.g. ~/skills and
the implicit ~/.cecli/skills default) last. Exact duplicate directory
paths are also dropped.

When no skills_paths is configured, the default search directory remains
~/.cecli/skills (unchanged).

…; revert skills tests to main

- Order skill dirs local-first, home last so first occurrence wins
- Reduce added comments to single lines
- Revert tests/basic/test_skills.py to main version (removes test churn)

skills: deduplicate same-named skills, prefer local over home directo…