docs: update all documentation for 80-test smoke suite + Rump Kernel status

docs: update all documentation for 80-test smoke suite + Rump Kernel status

- README.md: 44→80 smoke tests, add condition variables/TSC ns clock/IRQ chaining/
  FPU-SSE/Rump Kernel scaffold to features, update Status section, add src/rump/
  to directory structure
- POSIX_ROADMAP.md: 44→80 test count, update clock_gettime to TSC ns precision,
  update flock description, add Rump Kernel phases to Remaining Work
- TESTING_PLAN.md: 44→80 test count with expanded test categories
- SUPPLEMENTARY_ANALYSIS.md: add Rump Kernel to remaining enhancements,
  update test counts in conclusion