Adds Hamilton Helmer's 7 Powers framework skill for assessing durable
competitive advantage (scale economies, network effects, counter-
positioning, switching costs, branding, cornered resource, process
power). Updates skill counts and descriptions across marketplace.json,
plugin.json, and READMEs.
Merged from louzhedong:codex/add-seven-powers-skill (PR vs phuryn/pm-skills).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KcEyZ9gTqwkoiDBfW4fVzu
justin
Pawel Huryn