Named practitioners, harder topics, and mid-tier level fill-in

[gothosvc]

Adds a "Named Practitioners" naming convention (Bigby's Hand, corporate edition) plus 20 findings:

• MECHANICS.md — eponym convention (possessive or named-principle form, never a role, so it can't collide with Classes); Conviction, a resource pool exclusive to Halloran's line.
• Voss, The Halloran Principle, Delacroix — 9 spells across org-design, finance, analytics-forecasting, stakeholder-management, marketing-optics, and compliance-risk.
• Harder-topic findings — 10b5-1 Plan (insider trading), Facilitation Payment (foreign bribery), Personnel Matter (misconduct cover-up, aimed at the institutional mechanism, not the underlying conduct).
• Mid-tier (4th-7th level) fill-in — Due Diligence, D&O Insurance, Leveraged Buyout, Spin-Off, Astroturfing, Narrative Control, Proxy Fight, and Total Rewrite (the missing apex for Legacy Systems).

All new/changed spell files pass .github/scripts/validate_spell.py.