test(bmad-module): track fixture .mcp.json so CI install test passes

The acme-devlog fixture's .mcp.json was swallowed by the global
.gitignore '.mcp.json' rule, so it was never committed. The skill's
install test asserts _bmad/devlog/.mcp.json exists, which passed
locally (file on disk) but failed on CI's clean checkout. Add a
negation for the test-fixtures path and commit the fixture.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitignore

@@ -48,6 +48,9 @@ CLAUDE.local.md
 .junie/
 .agents/
 
+# Test fixtures need a committed .mcp.json (the rule above ignores real projects')
+!src/core-skills/bmad-module/tests/fixtures/**/.mcp.json
+
 z*/
 !docs/zh-cn/
 

src/core-skills/bmad-module/tests/fixtures/examples/comprehensive/acme-devlog/.mcp.json

@@ -0,0 +1,11 @@
+{
+  "mcpServers": {
+    "devlog-history": {
+      "command": "node",
+      "args": ["${CLAUDE_PLUGIN_ROOT}/scripts/mcp-server.js"],
+      "env": {
+        "DEVLOG_PATH": "${CLAUDE_PLUGIN_DATA}/devlog"
+      }
+    }
+  }
+}