⚡ Cache installation ID in memory to prevent repeated synchronous file reads

[TrueAlpha-spiral]

💡 What: The getInstallationId function in packages/core/src/utils/user_id.ts was updated to cache the installation ID in a module-level variable (cachedInstallationId).

🎯 Why: The function was performing a synchronous file read (fs.existsSync and fs.readFileSync) every time it was called. This function is called frequently (e.g., in telemetry logging paths for every single event), causing unnecessary I/O blocking.

📊 Measured Improvement:
By adding a simple memory cache to store the ID once read or generated, we see roughly a ~100x performance improvement.

• Baseline: ~19.3ms for 1000 calls.
• Improved: ~0.13ms for 1000 calls.

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PR created automatically by Jules for task 10579217545804489674 started by @TrueAlpha-spiral

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