* Add install.ps1 PowerShell wrapper and tests
Add a Windows-native PowerShell wrapper (install.ps1) that resolves symlinks and delegates to the Node-based installer runtime. Update README with PowerShell usage examples and cross-platform npx entrypoint guidance. Point the ecc-install bin to the Node installer (scripts/install-apply.js) in package.json (and refresh package-lock), include install.ps1 in package files, and add tests: a new install-ps1.test.js and a tweak to install-sh.test.js to skip on Windows. These changes provide native Windows installer support while keeping npm-compatible cross-platform invocation.
* Improve tests for Windows HOME/USERPROFILE
Make tests more cross-platform by ensuring HOME and USERPROFILE are kept in sync and by normalizing test file paths for display.
- tests/lib/session-adapters.test.js: set USERPROFILE when temporarily setting HOME and restore previous USERPROFILE on teardown.
- tests/run-all.js: use a normalized displayPath (forward-slash separated) for logging and error messages so output is consistent across platforms.
- tests/scripts/ecc.test.js & tests/scripts/session-inspect.test.js: build envOverrides from options.env and add HOME <-> USERPROFILE fallbacks so spawned child processes receive both variables when only one is provided.
These changes prevent test failures and inconsistent logs on Windows where USERPROFILE is used instead of HOME.
* Fix Windows paths and test flakiness
Improve cross-platform behavior and test stability.
- Remove unused createLegacyInstallPlan import from install-lifecycle.js.
- Change resolveInstallConfigPath to use path.normalize(path.join(cwd, configPath)) to produce normalized relative paths.
- Tests: add toBashPath and normalizedRelativePath helpers to normalize Windows paths for bash and comparisons.
- Make cleanupTestDir retry rmSync on transient Windows errors (EPERM/EBUSY/ENOTEMPTY) with short backoff using sleepMs.
- Ensure spawned test processes receive USERPROFILE and convert repo/detect paths to bash format when invoking bash.
These changes reduce Windows-specific failures and flakiness in the test suite and tidy up a small unused import.
