Digital platforms increasingly govern competition through algorithmically administered rules that allocate visibility, subsidies, commissions, participation opportunities, and sanctions. This article reconstructs ``platform-driven involution'' as a testable, portfolio-based theory-of-harm framework rather than a freestanding antitrust offense. Its application remains anchored in market definition, dominance, identified conduct under Article 22 of China's Anti-Monopoly Law, causal proof, competitive effects, and objective justification. The article clarifies that ecosystem analysis supplements rather than replaces relevant-market analysis and develops an evidence architecture for separating platform-induced effects from macroeconomic, demand, cost, and merchant-specific confounders. It then distinguishes preventive measures already supported by Chinese hard law or voluntary compliance guidance from compulsory competition-specific filing and pre-deployment assessment that would require clearer future authorization. The 2026 Trip.com decision is used to show how traffic allocation, exclusivity, lowest-price requirements, technical monitoring, and sanctions can form an integrated abuse architecture while liability remains tied to established statutory categories. Comparative analysis of EU platform regulation and Google Shopping supports calibrated procedural prevention, meaningful explanation, and causal discipline without protecting inefficient competitors or condemning aggressive competition.