Clear tmp directory when switching controller versions

[Copilot]

When integration tests switch between controller versions (e.g., dev → latest), leftover node_modules and data directories cause version conflicts and stale state.

Changes

Version tracking via .controller-version file:

• getInstalledControllerVersion() - reads current version from tracking file
• saveControllerVersion() - persists version after installation
• getControllerVersionFilePath() - returns path to tracking file

Automatic cleanup on version change:

• clearTmpDirectory() - empties node_modules and data directories
• prepareTestDir() - detects version changes and clears before installation

Behavior

// First run with 'dev' - installs and saves version
await controllerSetup.prepareTestDir('dev');

// Same version - skips cleanup, fast npm install
await controllerSetup.prepareTestDir('dev');

// Version change - clears directories, fresh install
await controllerSetup.prepareTestDir('latest');

Version changes trigger cleanup; same version preserves state for faster subsequent runs.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Clear tmp directory when switching controller versions</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Clear tmp directory when switching controller versions #526

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