Add Insight diagnostic batch foundation

[josiahking]

Summary

• Add the optional evolvephp/insight package with bounded diagnostic batch collection.
• Integrate Insight as the thirteenth normal release package.
• Preserve Core independence while consuming the existing observation sink contract.
• Extend release, architecture, documentation, workspace and prerelease-consumer coverage.
• Harden release validation for the thirteen-package inventory and isolate synthetic consumer fixture tags from source release tags.

Validation

• Root and package Composer validation passed.
• Deterministic package split validation passed for all 13 release packages.
• Prerelease consumer validation passed for alpha and stable dependency cases.
• Skeleton create-project validation passed offline.
• Supply-chain validation passed.
• Architecture, static analysis and style checks passed.
• Root test suite passed with 980 tests, 4039 assertions and 1 skipped test.