Remove evaluative epithets and copula-avoidance phrasing left from
AI-assisted writing ("представляет собой", "идеальный", "просто");
academic register, terms kept stable across ru/EN.

- README.md: fix broken make-commands table (make clean row was
  pushed out by an inline paragraph about bench/)
- docs/HISTORY.md: replace 23 checkmark emoji in section headings
  with a textual "(завершено)" marker
- SPECIFICATION/ROADMAP + func/{ru,EN}/{benchmarks,nix,pacman}:
  drop "ideal/perfectly clean/simple" wording in favor of facts

CHANGELOG entries are untouched per repo convention (journal files).