#2118: replace java.io.File usages with java.nio.file.Path

[maybeec]

This PR fixes #2118

Implemented changes:

Removed all remaining java.io.File imports in favor of the java.nio.file.Path / Files API as required by the coding conventions ("Obsolete APIs": java.io.File → use java.nio.file.Path). These were latent violations because CI Checkstyle only runs on changed files.

• PipRepositoryMock, MvnRepositoryMock, NpmRepositoryMock (test): File.separatorChar → FileSystems.getDefault().getSeparator() (NIO-native separator accessor).
• EclipseWorkspaceLockChecker (main): isLocked(File) → isLocked(Path), new File(args[0]) → Path.of(...), isFile() → Files.isRegularFile(...); RandomAccessFile is fed via inline .toFile(). Also replaced the pre-existing System.out usage message (a Checkstyle violation surfaced by editing the file) with the SLF4J logger.
• EclipseWorkspaceLockCheckerTest (test): File.createTempFile → Files.createTempFile, new File → Path.of, .delete() → Files.deleteIfExists.
• Eclipse.java (main): fixed stale {@link File} javadoc on isLocked(Path) (parameter was already Path) and dropped the now-unused import.
• ProjectManagerTest (gui): File + createNewFile() → Files.createFile; File + renameTo() → Files.move (rename success is now asserted via target-exists / source-gone).
• SystemPath (main): File.pathSeparatorChar → System.getProperty("path.separator").charAt(0) (there is no NIO accessor for the PATH-list separator).

After this change grep -rn "import java.io.File;" --include=*.java returns nothing.

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Testing instructions

1. Run mvn clean test — all tests pass. Affected tests were verified individually: SystemPathTest, EclipseWorkspaceLockCheckerTest, MvnRepositoryTest, MvnTest, NpmTest, PipTest (cli) and ProjectManagerTest (gui).
2. Run Checkstyle on the changed files, e.g. mvn checkstyle:check — 0 violations; in particular no IllegalImport for java.io.File.
3. Confirm no illegal import remains: grep -rn "import java.io.File;" --include=*.java returns nothing.

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Checklist for this PR

• When running mvn clean test locally all tests pass and build is successful
• PR title is of the form #«issue-id»: «brief summary» (e.g. #921: fixed setup.bat). If no issue ID exists, title only.
• PR top-level comment summarizes what has been done and contains link to addressed issue(s)
• PR and issue(s) have suitable labels
• Issue is set to In Progress and assigned to you or there is no issue (might happen for very small PRs)
• You followed all coding conventions
• You have added the issue implemented by your PR in CHANGELOG.adoc unless issue is labeled with internal — internal cleanup, no CHANGELOG entry needed
• You have formulated clear instructions on how to test your contribution under "Testing instructions"

[coveralls]

Coverage Report for CI Build 28849024574

Coverage increased (+0.03%) to 72.096%

Details

• Coverage increased (+0.03%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 23 coverage regressions across 3 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

23 previously-covered lines in 3 files lost coverage.

File	Lines Losing Coverage	Coverage
com/devonfw/tools/ide/locking/EclipseWorkspaceLockChecker.java	8	39.29%
com/devonfw/tools/ide/tool/eclipse/Eclipse.java	8	63.29%
com/devonfw/tools/ide/common/SystemPath.java	7	89.07%

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Coverage Stats

Relevant Lines:	16559
Covered Lines:	12437
Line Coverage:	75.11%
Relevant Branches:	7434
Covered Branches:	4861
Branch Coverage:	65.39%
Branches in Coverage %:	Yes
Coverage Strength:	3.18 hits per line

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💛 - Coveralls