build: dynamically tangle to INSTALL_DIR without copying .org files

- Updated all 150+ :tangle headers across harness/ and skills/ to use elisp (expand-file-name) to target INSTALL_DIR dynamically.
- Cleaned up environment/ directory depth by moving memory-image.lisp to state/.
- Moved test scripts to tests/ and deleted redundant chat scripts.

skills/org-skill-llama-backend.org

@@ -21,12 +21,12 @@ This skill acts as a proxy between the OpenCortex kernel and the Lisp-agnostic `
 * Phase D: Build (Implementation)
 
 ** Package Context
-#+begin_src lisp :tangle ./org-skill-llama-backend.lisp
+#+begin_src lisp :tangle (expand-file-name "org-skill-llama-backend.lisp" (concat (or (getenv "INSTALL_DIR") ".") "/skills"))
 (in-package :opencortex)
 #+end_src
 
 ** The Inference Engine (llama-inference)
-#+begin_src lisp :tangle ./org-skill-llama-backend.lisp
+#+begin_src lisp :tangle (expand-file-name "org-skill-llama-backend.lisp" (concat (or (getenv "INSTALL_DIR") ".") "/skills"))
 (defun llama-inference (prompt system-prompt &key (model "local-model"))
   "Sends a completion request to the local llama.cpp server."
   (let ((endpoint (uiop:getenv "LLAMACPP_ENDPOINT")))
@@ -51,7 +51,7 @@ This skill acts as a proxy between the OpenCortex kernel and the Lisp-agnostic `
 #+end_src
 
 ** Registration
-#+begin_src lisp :tangle ./org-skill-llama-backend.lisp
+#+begin_src lisp :tangle (expand-file-name "org-skill-llama-backend.lisp" (concat (or (getenv "INSTALL_DIR") ".") "/skills"))
 (progn
   (register-probabilistic-backend :llama #'llama-inference)
   (harness-log "LLAMA: Local backend registered and active."))