chore(config): add Obsidian MCP server and bin plugin

## Why
The Obsidian MCP server (mcpvault) wasn't wired up in this repo's local
config, making obsidian tools unavailable. The bin@holocron plugin was
added to settings but not yet listed in the allowed plugins.

## Impact
- Obsidian MCP tools are now available when working in this repo
- bin@holocron plugin is enabled in .claude/settings.json

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/settings.json

@@ -3,6 +3,7 @@
     "PreToolUse": []
   },
   "enabledPlugins": {
-    "kyberforge@holocron": true
+    "kyberforge@holocron": true,
+    "bin@holocron": true
   }
 }