Fix Rider plugin IOException for non-local VFS files

[rcdailey]

Summary

Filter out non-local virtual files (git index, JARs, etc.) in the Rider plugin's document change listener to prevent IOException when ProcessBuilder receives an invalid working directory.

Problem

The plugin's documentChanged listener receives events from all virtual file systems, including Rider's git index VFS (GitIndexFileSystemRefresher). These files have paths like 7fa4270e:/home/user/project:/home/user/project/src/File.cs which are internal VFS identifiers, not valid filesystem paths. When this path is used as a ProcessBuilder working directory, it fails with:

java.io.IOException: Cannot run program "/usr/lib64/dotnet/dotnet"
  (in directory "7fa4270e:/home/robert/code/recyclarr-workspace/recyclarr:..."):
  error=2, No such file or directory

This is a regression of #1691, which attempted to fix the same issue using getCanonicalPath() with a fallback to getPath(). The fallback still fires because getCanonicalPath() returns null for git index VFS files.

Fix

Replace the getCanonicalPath()/getPath() fallback with an isInLocalFileSystem() guard that skips non-local files entirely. For files that pass this check, getPath() always returns a valid local path, so the canonical path logic and its fallback are removed as dead code.

[belav]

Looks good! I'll get a new version published shortly but it can take a couple of days for jetbrains to approve it.