Resolve clusterio through CLUSTERIO rather than in ci only

The library path was injected by the workflow, so an editor opened on
this repo could not resolve `modules/clusterio/*`. It now comes from
the environment in both places.

It cannot be written relative to this repo: emmylua does not normalise
`..` in a library path, and an absolute path containing `..` fails the
same way, so the location has to come from outside.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.emmyrc.json

@@ -6,6 +6,8 @@
     },
     "workspace": {
         "$comment-moduleMap": "Replaces the fmtk --clusterio-modules plugin, rewrites each file's own module path rather than the require string",
+        "$comment-library": "clusterio is outside this repo, set CLUSTERIO to your checkout. The factorio typedefs come from .luarc.json, which the factoriomod-debug extension manages",
+        "library": [ "$CLUSTERIO/packages/host" ],
         "ignoreDir": [ ".github", "web", "dist", "factorio" ],
         "ignoreGlobs": [ "**/node_modules/**", "**/dist/**" ],
         "moduleMap": [