Add the shared Claude Remote Control setup

Units, settings and setup README for the claude-rc user, which serves my projects' read-only MCP servers to the Claude app (negsplit for now).

.config/claude-rc/project-settings.json

@@ -0,0 +1,36 @@
+{
+  "permissions": {
+    "defaultMode": "default",
+    "disableBypassPermissionsMode": "disable",
+    "disableAutoMode": "disable",
+    "allow": [
+      "mcp__negsplit",
+      "Read(~/.local/share/negsplit/charts/**)"
+    ],
+    "deny": [
+      "Read(~/.config/**)",
+      "Read(~/.claude/**)",
+      "Read(~/.claude.json)",
+      "Edit(~/.config/**)",
+      "Edit(~/.claude/**)",
+      "Edit(~/.claude.json)",
+      "Edit(./.claude/**)",
+      "Edit(./.mcp.json)",
+      "WebFetch",
+      "WebSearch"
+    ]
+  },
+  "sandbox": {
+    "enabled": true,
+    "failIfUnavailable": true,
+    "allowUnsandboxedCommands": false,
+    "autoAllowBashIfSandboxed": true,
+    "filesystem": {
+      "denyRead": ["~/.config", "~/.claude", "~/.claude.json"],
+      "denyWrite": ["./.claude", "./.mcp.json"]
+    },
+    "network": {
+      "allowedDomains": []
+    }
+  }
+}