chore: add .mcp.json (brain + gitea) — wire tapir for the single-harness workflow

tapir had no MCP config at all — a hyperguild session here couldn't reach brain
or Gitea, breaking the report-back path before it could start. Matches the
shape now standard post-consolidation (hyperguild#75/#76, infra#178 template
refresh). Prerequisite for tapir#20 being run as the first real workflow test.

.mcp.json

@@ -0,0 +1,18 @@
+{
+  "mcpServers": {
+    "brain": {
+      "type": "http",
+      "url": "https://brain-mcp.d-ma.be/mcp",
+      "headers": {
+        "Authorization": "Bearer ${BRAIN_MCP_TOKEN}"
+      }
+    },
+    "gitea": {
+      "type": "http",
+      "url": "https://git-mcp.d-ma.be/mcp",
+      "headers": {
+        "Authorization": "Bearer ${GITEA_MCP_TOKEN}"
+      }
+    }
+  }
+}