chore: vendor blender-mcp as a git submodule alongside godot-mcp

Both mcp/godot-mcp and mcp/blender-mcp were already cloned locally and
registered in .gitmodules/.mcp.json/CLAUDE.md, but neither submodule's
gitlink had actually been committed, so a fresh clone wouldn't pull
either down. Stages the two gitlinks so `git submodule update --init
--recursive` works as documented.

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "mcp/godot-mcp"]
 	path = mcp/godot-mcp
 	url = https://github.com/tugcantopaloglu/godot-mcp.git
+[submodule "mcp/blender-mcp"]
+	path = mcp/blender-mcp
+	url = https://github.com/ahujasid/blender-mcp.git