feat(claudeconfig): add dotslash stack

Adds sandbox allowWrite for ~/Library/Caches/dotslash and
Bash(dotslash:*) permission, following the per-subdirectory
pattern used by safehouse and all other stacks.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: technicalpickles

claude/stacks/dotslash.jsonc

@@ -0,0 +1,16 @@
+{
+  // DotSlash tool launcher (Meta)
+  "permissions": {
+    "allow": [
+      "Bash(dotslash:*)"
+    ]
+  },
+
+  "sandbox": {
+    "filesystem": {
+      "allowWrite": [
+        "~/Library/Caches/dotslash"
+      ]
+    }
+  }
+}