Remove dead code scripts

Deleted 4 unused scripts:
- loader.mjs - deprecated ESM loader, replaced by register-loader.mjs + alias-loader.mjs
- coverage-percent.mjs - standalone reporter, subsumed by cover script
- sync-scripts.mjs - one-time utility with outdated project list
- taze.mjs - duplicate logic now in update.mjs

These scripts were never referenced in package.json.

Author: jdalton