Add read-only PI tools: get_planets (colonies), get_planet_layout
(pins/links/routes), get_corp_customs_offices. ESI exposes no PI write
endpoint despite the manage_planets scope name, so these are reads.
Closes#29. 132 tests, coverage 90%, 84 tools.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
