fix(boot): Point SKILLS_DIR to repo skills/ folder and improve boot failure error messages

src/skills.lisp

@@ -205,7 +205,7 @@
                                    '("org-skill-policy" "org-skill-bouncer"))))
         (dolist (req mandatory-skills)
           (unless (member req sorted-files :key #'pathname-name :test #'string-equal)
-            (error "BOOT FAILURE: Mandatory skill '~a' not found in skills directory." req)))
+            (error "BOOT FAILURE: Mandatory skill '~a' not found in skills directory: ~a" req (uiop:native-namestring skills-dir))" req)))
       
         (harness-log "==================================================")
         (harness-log " LOADER: Initializing ~a skills..." (length sorted-files))