perf(mcp): reach brain and infra over tailnet NodePorts, not the public edge

Every MCP call from Claude Code was going out through claude.ai's connector
infrastructure, across the public internet, through Cloudflare and NPM on
piguard, back into koala's k3s ingress — to reach a service on the same
machine the session is running on. For brain that means a two-cloud round trip
to read /var/lib/supervisor/brain, a file on koala's local disk.

Cloudflare rate-limits and size-caps tool results on that path, which is the
actual user-facing symptom. Measured from koala:

  brain  koala:30330    200 in  6.8ms
  infra  koala:30342    200 in  3.6ms
  brain  public edge    200 in 27.7ms

infra starts working again as a side effect: its only fault was an SNI/cert
gap at the public edge (TLS "unrecognized name"), which the NodePort path does
not traverse. No NPM change needed for local use.

Note this is not a relocation of existing config. The mcpServers block that
lived in ~/.claude/settings.json was inert — Claude Code reads server
definitions from ~/.claude.json, project .mcp.json, plugins and connectors,
not from settings.json. Verified: a uniquely-named server placed there is
invisible to both `claude mcp list` and `claude mcp get`. So before the plugin
existed, koala had no direct path at all and every call went via Cloudflare by
construction. That also explains how a stale GITEA_MCP_TOKEN went unnoticed
for five days: nothing consumed it.

Safe to land now because koala is the only host with the plugin installed
(#24). The koala firewall must allow 30330/30342 on the Tailscale interface —
NOT on the LAN broadly, so tailnet membership stays the perimeter — before the
Macs get the plugin. Tracked as a prerequisite in #24. Measured today: those
ports are refused from iguana over both LAN and tailnet while :22 answers, so
the rule does not exist yet.

Bump-Type: minor

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BeAp5LTscnz2W7Ubt4eJ6m

.mcp.json

@@ -1,15 +1,16 @@
 {
+  "_comment": "Tailnet-direct NodePorts, not the public d-ma.be hostnames. The public path goes out through Cloudflare and NPM to reach a k3s service on koala, which imposes rate limits and message-size caps on tool results and adds a full internet round trip - for a service on the same machine most sessions run on. Requires koala to allow these ports on the Tailscale interface; see mathias/skills#24.",
   "mcpServers": {
     "brain": {
       "type": "http",
-      "url": "https://brain-mcp.d-ma.be/mcp",
+      "url": "http://koala:30330/mcp",
       "headers": {
         "Authorization": "Bearer ${BRAIN_MCP_TOKEN}"
       }
     },
     "infra": {
       "type": "http",
-      "url": "https://infra-mcp.d-ma.be/mcp"
+      "url": "http://koala:30342/mcp"
     }
   }
 }