registry: server.json + mcp-name ownership marker in README (official MCP Registry prerequisites)

- server.json: schema 2025-12-11, registryType pypi, name io.github.nickoscope/nickol-knx-mcp,
  stdio transport, NICKOL_KNX_WORKSPACE / NICKOL_KNX_CATALOG documented as optional env vars
- README: <!-- mcp-name: io.github.nickoscope/nickol-knx-mcp --> (becomes the PyPI description,
  which is what the registry checks for ownership)
- verified: uv build produces sdist+wheel, twine check PASSED, marker present in wheel METADATA

CHANGELOG.md

@@ -8,6 +8,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- **Official MCP Registry preparation**: `server.json` (schema 2025-12-11, `registryType: pypi`,
+  server name `io.github.nickoscope/nickol-knx-mcp`, stdio transport, the two optional env vars) and the
+  ownership marker `<!-- mcp-name: … -->` in the README, which the registry checks inside the published
+  PyPI description. Package builds clean (`uv build`, `twine check` PASSED). Publishing itself still needs
+  a PyPI token (owner action), then `mcp-publisher login github && mcp-publisher publish`.
+
+### Added
+
 - **`suggest.py` — structure-first entity suggestions (experimental, library-only, no MCP tool yet).**
   Prototype of a second Home Assistant KNX `SuggestionProvider` (core PR #180891 contract): device
   channel → communication-object flags (write = command sink, transmit = status source) → DPT pattern

README.md

@@ -1,5 +1,7 @@
 # nickol-knx-mcp
 
+<!-- mcp-name: io.github.nickoscope/nickol-knx-mcp -->
+
 **A design-time KNX / ETS6 assistant exposed as an [MCP](https://modelcontextprotocol.io) server.**
 
 Four things you can do with it — all **without ever touching the live KNX bus**:

server.json

@@ -0,0 +1,34 @@
+{
+  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
+  "name": "io.github.nickoscope/nickol-knx-mcp",
+  "title": "nickol-knx",
+  "description": "Design-time KNX/ETS assistant: read-only .knxproj analysis (naming, DPT, command/status pairing, KNX Secure, topology), device decomposition, and generation of Home Assistant YAML, ETS exports and an as-built handover pack. No live-bus access.",
+  "version": "0.8.0",
+  "repository": {
+    "url": "https://github.com/NickoScope/nickol-knx-mcp",
+    "source": "github"
+  },
+  "websiteUrl": "https://nickoscope.github.io/nickol-knx-mcp",
+  "packages": [
+    {
+      "registryType": "pypi",
+      "identifier": "nickol-knx-mcp",
+      "version": "0.8.0",
+      "transport": {
+        "type": "stdio"
+      },
+      "environmentVariables": [
+        {
+          "name": "NICKOL_KNX_WORKSPACE",
+          "description": "Directory the server may write generated files into (reports, HA YAML, ETS exports). Defaults to ./knx-workspace",
+          "isRequired": false
+        },
+        {
+          "name": "NICKOL_KNX_CATALOG",
+          "description": "Optional path to a local device catalog for exact vendor decomposition",
+          "isRequired": false
+        }
+      ]
+    }
+  ]
+}