Add exists() and isDirectory() methods to IFileStore

[HannesWell]

Add the methods IFileStore.exists() and IFileStore.isDirectory() methods.

The new methods make the corresponding methods more convenient to use and allow subsequent optimizations of their implementation.

There are further potential callers in the eclipse.platform.ui, JDT and PDE repositories.

[eclipse-platform-bot]

This pull request changes some projects for the first time in this development cycle.
Therefore the following files need a version increment:

resources/examples/org.eclipse.ui.examples.filesystem/META-INF/MANIFEST.MF

An additional commit containing all the necessary changes was pushed to the top of this PR's branch. To obtain these changes (for example if you want to push more changes) either fetch from your fork or apply the git patch.

Git patch

From 9b3ba1f855314a76f3bf600edc65509cb5581605 Mon Sep 17 00:00:00 2001
From: Eclipse Platform Bot <platform-bot@eclipse.org>
Date: Sat, 19 Sep 2026 12:47:39 +0000
Subject: [PATCH] Version bump(s) for 4.42 stream


diff --git a/resources/examples/org.eclipse.ui.examples.filesystem/META-INF/MANIFEST.MF b/resources/examples/org.eclipse.ui.examples.filesystem/META-INF/MANIFEST.MF
index 325dc32f3e..b2a8ed32f2 100644
--- a/resources/examples/org.eclipse.ui.examples.filesystem/META-INF/MANIFEST.MF
+++ b/resources/examples/org.eclipse.ui.examples.filesystem/META-INF/MANIFEST.MF
@@ -3,7 +3,7 @@ Bundle-ManifestVersion: 2
 Automatic-Module-Name: org.eclipse.ui.examples.filesystem
 Bundle-Name: Efs Examples Plug-in
 Bundle-SymbolicName: org.eclipse.ui.examples.filesystem;singleton:=true
-Bundle-Version: 1.2.100.qualifier
+Bundle-Version: 1.2.200.qualifier
 Bundle-Vendor: Eclipse.org
 Require-Bundle: org.eclipse.core.filesystem,
  org.eclipse.core.resources,
-- 
2.55.0

Further information are available in Common Build Issues - Missing version increments.

[github-actions]

Test Results

    54 files  ±0      54 suites  ±0   59m 11s ⏱️ -23s
 4 810 tests ±0   4 788 ✅ ±0   22 💤 ±0  0 ❌ ±0 
12 321 runs  ±0  12 168 ✅ ±0  153 💤 ±0  0 ❌ ±0 

Results for commit 1ee814b. ± Comparison against base commit 2d15cf3.