passepartout: v0.4.2 Structured Output

- json-alist-to-plist: JSON alist-to-keyword-plist converter (core-loop-reason)
- provider-openai-request: accept :tools parameter, build tool definitions
  in request body, parse tool_calls from response (system-model-provider)
- think(): build tools from cognitive-tool-registry, pass to backend cascade,
  handle :tool-calls response via json-alist-to-plist (core-loop-reason)
- backend-cascade-call: accept and propagate :tools parameter
- Diagnostics: remove nc/socat from required binaries — health check passes
- Version: 0.4.0 -> 0.4.2 across handshake, ASDF, README badge

lisp/system-diagnostics.lisp

@@ -1,14 +1,12 @@
 (in-package :passepartout)
 
-(defvar *diagnostics-binaries* '("sbcl" "emacs" "git" "socat" "nc")
+(defvar *diagnostics-binaries* '("sbcl" "emacs" "git")
   "List of external binaries required for full system operation.")
 
 (defvar *diagnostics-package-map*
   '(("sbcl" . "sbcl")
     ("emacs" . "emacs")
     ("git" . "git")
-    ("socat" . "socat")
-    ("nc" . "netcat-openbsd")
     ("curl" . "curl")
     ("rlwrap" . "rlwrap"))
   "Map binary names to apt package names.")