A tools bundle speaks MCP over stdio: the loop in TypeScript, and skeleton SDKs for Python, Go, Rust and C (hq ADR 0187)

The node's runtime launches a tools bundle as a process and speaks MCP over stdio to it, so a tool
may be written in any language and the transport stays in the runtime (ADR 0039's refusal, kept).
Each SDK is the loop and the tool type and nothing else: `@novox/mesh-sdk/stdio` (serveStdio, and
serveRegisteredOverStdio for a bundle that already registers the in-process way), python/, go/,
rust/ and c/ beside it, each with an example answering `greet` and the seat verb `node-lamp.on`.
Skeletons, by the operator's direction: the bare minimum one bundle per language needs to be built
and answer, proven here by each example answering tools/list and tools/call on stdio.

python/README.md

@@ -0,0 +1,8 @@
+# mesh-sdk for Python
+
+The skeleton (novox/hq ADR 0187): `mesh_sdk.serve(name, tools)` speaks MCP over stdio to the node's
+tool runtime. A `Tool` is a name, a description, an argument schema and a function. A tool named
+`<seat>.<verb>` is the seat's implementation. No dependencies beyond the standard library.
+
+What it holds, under ADR 0039's test: the stdio loop and the tool type. Nothing else — no bus, no
+client, nothing of any module's. Run `./example.py` and type a `tools/list` request to see it answer.