[Anand Krishnamoorthi (anakrish)]

Summary

• Run the core debug workflow on both Ubuntu and Windows using an OS matrix.
• Disable fail-fast so each platform reports its result independently, and use Bash consistently.
• Make allocation overflow coverage deterministic by testing projected-usage arithmetic with explicit live usage instead of assuming tracked test-harness allocations.
• Cover both overflow rejection and exact-limit acceptance, and run these unit tests alongside the allocator integration tests in the debug workflow.

Validation

• Both projected-allocation unit tests and all four allocator integration tests pass locally on Windows.
• Allocator Clippy checks pass with warnings denied; formatting and git diff --check pass.
• Parsed the workflow YAML and verified both platforms run the allocator regression tests.