fix(tests): prevent v8 coverage segfault on large codebase

[jdalton]

Summary

Fixes segmentation fault when running pnpm cover by implementing memory management and processing concurrency options for v8 coverage on our large test suite.

Requires #875.

Changes

1. Logger Hoisting (scripts/cover.mjs)

• Moved const logger = getDefaultLogger() to module scope
• Fixes ReferenceError in helper functions and catch blocks

2. Memory Management (package.json)

• Updated test:unit:coverage script to use NODE_OPTIONS environment variable
• Added --max-old-space-size=8192 to increase Node.js heap memory limit
• Prevents out-of-memory crashes during coverage processing

3. V8 Coverage Configuration (vitest.config.mts)

• Added processingConcurrency: 1 to prevent parallel processing overload
• Added reportOnFailure: true for better error reporting
• Added explicit reportsDirectory: './coverage' path

4. Updated Coverage Badges (README.md)

• Code Coverage: 37.17% (from placeholder 90%)
• Type Coverage: 98.16% (from placeholder 95%)

Problem

The v8 coverage provider was segfaulting with SIGSEGV when processing our test suite:

• 196 test files
• 2,255 tests
• Large codebase requiring substantial memory for coverage analysis

Root Cause

V8 coverage was attempting to process too much data simultaneously without sufficient memory allocation, causing the Node.js process to crash with a segmentation fault.

Solution

1. Increased memory limit: Node.js heap now has 8GB available for coverage processing
2. Sequential processing: Coverage reports are processed one at a time (processingConcurrency: 1)
3. Fixed logger scope: Prevents ReferenceError that was masking the real issue

Test Results

✓ Coverage now completes successfully:

• 196 test files passed
• 2,255 tests passed (2 skipped)
• Duration: 11.91s
• Type Coverage: 98.16%
• Code Coverage: 37.17%
• Cumulative: 67.66%

Related

This fix enables reliable coverage reporting for our large test suite and unblocks future coverage tracking improvements.