Release LowPack 0.1.2

[devkyato]

What changed

I rewrote LowPack's public documentation so it reads like one person explaining
what they built and why. The exact format tables, limits, security guarantees,
and benchmark numbers stay technical; the surrounding guidance is warmer,
shorter, and more narrative.

Oh! The review also caught a factual mismatch: the limitations page said source
dictionary training was inactive, even though LowPack already trains bounded,
deterministic dictionaries and authenticates them in the manifest. That is now
corrected.

Reader impact

• the README explains the original idea and honest alpha boundary in first
  person
• architecture, profiles, determinism, security, telemetry, and benchmarking
  now include the reasoning behind their design
• contribution and vulnerability guidance sound personal without becoming
  vague
• a new test keeps package version, changelog, Markdown links, and the cover
  image aligned

Validation

• 32 tests passed; one Windows symlink test skipped due unavailable privileges
• Ruff passed
• strict Mypy passed
• all local Markdown links and the cover asset passed the new integrity test
• wheel and sdist reproduced byte-for-byte
• clean v0.1.2 wheel install and pack/full-verify/unpack passed