chore(pkg): sync packaging metadata to v0.12.0

Every packaging surface states the newest v-prefixed tag, as the
version-metadata contract requires: the Chocolatey nuspec and installer
(checksum re-pinned to the released windows-amd64 archive), the Go
installer, the Nix flake, server.json, the npm and PyPI wrappers.

Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>

server.json

@@ -8,12 +8,12 @@
     "source": "github"
   },
   "websiteUrl": "https://deusdata.github.io/codebase-memory-mcp/",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "packages": [
     {
       "registryType": "npm",
       "identifier": "codebase-memory-mcp",
-      "version": "0.11.0",
+      "version": "0.12.0",
       "runtimeHint": "npx",
       "transport": {
         "type": "stdio"
@@ -22,7 +22,7 @@
     {
       "registryType": "pypi",
       "identifier": "codebase-memory-mcp",
-      "version": "0.11.0",
+      "version": "0.12.0",
       "runtimeHint": "uvx",
       "transport": {
         "type": "stdio"