Issue #2402 : Support ~ (tilde) at start of path to resolve ${user.home}

[mattcasters]

Fixes #2402

Description

In Apache Hop, specifying a path starting with ~ (e.g. ~/testenv or ~\testenv on Windows) resulted in a folder literally named ~ created inside the Hop installation base directory (user.dir), because neither standard Java nor Apache Commons VFS expands tilde to the user's home directory.

This PR adds system-wide support for ~ (tilde) at the start of paths to mean ${user.home} across Apache Hop on all platforms (including Windows with backslash \ separators).

Changes

• Core Virtual File System (hop-core):
  • Added HopVfs.resolveHomeDirectory(String path, IVariables variables) and HopVfs.resolveHomeDirectory(String path).
    • Expands exact ~, ~/..., ~\..., as well as file://~... and file:~... to ${user.home}.
    • Preserves non-start occurrences (e.g. /opt/hop/~, foo~bar, s3://bucket/~/key) and non-separator suffixes (e.g. ~username, ~temp).
    • Uses ${user.home} from IVariables when provided, falling back to System.getProperty("user.home").
  • Integrated resolveHomeDirectory into HopVfs.resolveWith() so that all file operations (getFileObject, fileExists, getInputStream, etc.) resolve tilde paths transparently.
  • Updated HopVfs.isAbsolutePath() to recognize tilde paths as absolute so they are not treated as relative to the working directory.
• Projects Plugin (hop-misc-projects):
  • Updated PathVariableReplacer.isCandidatePathValue() to accept tilde paths (~, ~/..., ~\...) for project variable rewriting.
  • Updated ProjectsMetadataExporter.resolveExportFilename() to use HopVfs.isAbsolutePath().
• Git Plugin (hop-misc-git):
  • Delegated CaseInsensitiveIgnores.replaceUserHome() to HopVfs.resolveHomeDirectory().
• Documentation:
  • Updated vfs.adoc documenting ~ under the File provider with POSIX and Windows syntax rules and examples.
  • Updated variables.adoc with a dedicated section on the ~ user home shortcut.
  • Updated projects-environments.adoc documenting that ~ can be used in the project Home folder and environment variables.
• Unit Tests:
  • Added unit test coverage in HopVfsTest and PathVariableReplacerTest.