Improve cache plugin API calls and improve logging

[scottrigby]

• Correct cache.restore() and cache.save() to use proper signature (path, { key })
• Add console.log statements for all cache operations with [CACHE] prefix
• Accumulate all operation results for combined deploy summary display
• Log environment variables at start for debugging cache key generation
• Track restore/save success and errors with clear status indicators

This ensures the plugin follows Netlify's cache-utils API documentation and provides visibility into cache operations during builds.

see:

• https://docs.netlify.com/extend/develop-and-share/develop-build-plugins/#plugin-methods
• https://github.com/netlify/build/blob/main/packages/cache-utils/README.md

[Copilot]

Pull request overview

This PR corrects the Netlify cache plugin API usage and significantly improves logging visibility. The changes align the plugin with Netlify's official cache-utils API documentation by fixing method signatures and add comprehensive console logging with a [CACHE] prefix to track all cache operations during builds.

Key changes:

• API Corrections: Fixed cache.restore() and cache.save() to use the correct signature (path, { key }) instead of the previous incorrect usage
• Enhanced Logging: Added console.log statements for all cache operations with clear status indicators (✓, ✗, ⚠, ⊖) and accumulation of results for a combined deploy summary
• Better Debugging: Added environment variable logging at startup and per-directory processing logs to help debug cache key generation issues

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[Copilot]

The environment object is being logged directly to console.log, which will output "[object Object]" instead of the actual values. To properly display the environment variables, either use JSON.stringify() or log each variable separately.

Suggested change

	console.log('[CACHE] Environment:', {
	CACHE_VERSION: process.env.CACHE_VERSION,
	CACHE_PER_BRANCH: process.env.CACHE_PER_BRANCH,
	NETLIFY_BRANCH: process.env.NETLIFY_BRANCH
	});
	console.log('[CACHE] Environment:', JSON.stringify({
	CACHE_VERSION: process.env.CACHE_VERSION,
	CACHE_PER_BRANCH: process.env.CACHE_PER_BRANCH,
	NETLIFY_BRANCH: process.env.NETLIFY_BRANCH
	}, null, 2));

[Copilot]

The onPostBuild function is missing the same environment variable logging that was added to onPreBuild. For consistency and debugging purposes, consider adding similar logging here to help track cache key generation during the save phase. This would help debug issues where save and restore operations might use different keys.

Suggested change

	console.log('[CACHE] ========== Cache Save Starting ==========');
	console.log('[CACHE] ========== Cache Save Starting ==========');
	console.log('[CACHE] Environment:', {
	CACHE_VERSION: process.env.CACHE_VERSION,
	CACHE_PER_BRANCH: process.env.CACHE_PER_BRANCH,
	NETLIFY_BRANCH: process.env.NETLIFY_BRANCH
	});

[Copilot]

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