AI default/tests: env-passed key, secure creation, harness install, isolated strict mocks

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QKxGW1raAWaqeU8WdHsMsp

bin/omarchy-cn-ai-default

@@ -29,6 +29,13 @@ codex) agent="codex" ;;
   ;;
 esac
 
+command=$(cn_ai_harness_field "$harness" command)
+if ! command -v "$command" > /dev/null 2>&1; then
+  install=$(cn_ai_harness_field "$harness" install)
+  echo "Installing $harness: $install"
+  $install
+fi
+
 key=$(omarchy-cn-ai-secret get "$provider")
 
 case "$harness" in
@@ -44,17 +51,21 @@ claude-code)
     current=$(cat "$settings")
     cp "$settings" "$settings.omarchycn-bak-$(date +%Y%m%d-%H%M%S)"
   fi
-  jq --arg base "$base" --arg key "$key" --arg model "$model" --arg fast "$fast" \
-    '.env = (.env // {}) + {
-      ANTHROPIC_BASE_URL: $base,
-      ANTHROPIC_AUTH_TOKEN: $key,
-      ANTHROPIC_API_KEY: $key,
-      ANTHROPIC_MODEL: $model,
-      ANTHROPIC_DEFAULT_SONNET_MODEL: $model,
-      ANTHROPIC_DEFAULT_OPUS_MODEL: $model,
-      ANTHROPIC_DEFAULT_HAIKU_MODEL: $fast
-    }' <<<"$current" > "$settings.omarchycn-new"
-  chmod 600 "$settings.omarchycn-new"
+  # Key reaches jq via environment, never the argument list
+  rm -f "$settings.omarchycn-new"
+  (
+    umask 077
+    CN_AI_KEY="$key" jq --arg base "$base" --arg model "$model" --arg fast "$fast" \
+      '.env = (.env // {}) + {
+        ANTHROPIC_BASE_URL: $base,
+        ANTHROPIC_AUTH_TOKEN: env.CN_AI_KEY,
+        ANTHROPIC_API_KEY: env.CN_AI_KEY,
+        ANTHROPIC_MODEL: $model,
+        ANTHROPIC_DEFAULT_SONNET_MODEL: $model,
+        ANTHROPIC_DEFAULT_OPUS_MODEL: $model,
+        ANTHROPIC_DEFAULT_HAIKU_MODEL: $fast
+      }' <<<"$current" > "$settings.omarchycn-new"
+  )
   mv "$settings.omarchycn-new" "$settings"
   ;;
 codex)