docs: sync Stage A baseline in Idea.md with simulation seeding

[Neoplayer]

Motivation

• Prevent documentation drift by making the Stage A example baseline in docs/Idea.md match the actual seeding logic in the simulation code.

Description

• Updated section 6.2) Стартовая конфигурация (пример) in docs/Idea.md to reflect 7 компаний (1 игроковая + 6 NPC, включая дополнительные hauler-компании) instead of the previous count.
• Made explicit that Stage A currently uses 60 NPC trade-кораблей and added a note that the canonical baseline is defined by the seeding functions seed_stage_a_companies and seed_stage_a_ships.

Testing

• Ran rg to locate seed_stage_a_companies and seed_stage_a_ships and confirmed the companies list and the for idx in 0..60 ship generation loop, and the check succeeded.
• Printed and inspected the updated docs/Idea.md block with sed and nl to verify the textual updates, and the inspection succeeded.

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Codex Task