feat: add DeepSeek and NVIDIA NIM providers

- Add deepseek and nvidia entries to gateway-provider config

- Add DEEPSEEK_API_KEY and NVIDIA_API_KEY to .env.example

- Add deepseek and nvidia to doctor's LLM provider check

- Fix remaining harness-log → log-message reference

lisp/security-vault.lisp

@@ -0,0 +1,25 @@
+(defvar *vault-memory* (make-hash-table :test 'equal)
+  "In-memory cache of sensitive credentials.")
+
+(defun vault-get (provider &key (type :api-key))
+  "Retrieves a credential from the vault or environment."
+  (let* ((key (format nil "~a-~a" provider type))
+         (val (gethash key *vault-memory*)))
+    (if val
+        val
+        (let ((env-var (case provider
+                          (:gemini "GEMINI_API_KEY")
+                          (:openai "OPENAI_API_KEY")
+                          (:anthropic "ANTHROPIC_API_KEY")
+                          (:openrouter "OPENROUTER_API_KEY")
+                          (otherwise nil))))
+          (when env-var (uiop:getenv env-var))))))
+
+(defun vault-set (provider secret &key (type :api-key))
+  "Stores a secret in the vault."
+  (let ((key (format nil "~a-~a" provider type)))
+    (setf (gethash key *vault-memory*) secret)))
+
+(defskill :passepartout-security-vault
+  :priority 600
+  :trigger (lambda (ctx) (declare (ignore ctx)) nil))