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/core-defpackage.lisp

@@ -62,7 +62,7 @@
     #:loop-gate-reason
     #:cognitive-verify
     #:backend-cascade-call
-    #:register-pre-reason-handler
+    #:json-alist-to-plist
     #:inject-stimulus
     #:stimulus-inject
     #:hitl-create