BM-1841: Add functionality to wizard for estimating infra costs and zkc subsidy

[capossele]

Extends the prover generate-config wizard with optional infrastructure cost estimation and a cost-based pricing floor. The wizard can now derive a minimum price from the user’s hourly infra cost and ZKC subsidy, compare it to market levels, and recommend a floor that keeps the prover profitable while staying comparable to the market.

Changes:

• Hourly infra cost (Step 7): New prompt for hourly infra cost (USD). Default 0; if 0, cost-based logic is skipped and behavior stays market-percentile only.
• ZKC subsidy: Fetches POVW epochs API, computes average ZKC per Mcycle, converts to USD via price oracle. Used as baseline income and subtracted from infra cost to get cost floor.
• Cost breakdown: shows infra cost, ZKC subsidy, and cost floor per BCycle; cost floor is capped by $0.10/BCycle benchmark.
• Recommendation: If cost >= 0, recommends cost-based floor (or market 25th percentile when cost floor is 0). Shows both floor and market 25th; warns only when floor is above market.
• BCycle UX: Pricing and collateral prompts use “per BCycle”; values are converted to per Mcycle for broker.toml.
• Config: When cost-based, adds a comment to min_mcycle_price explaining how it was derived.

Example:

[linear]

BM-1841 Add functionality to wizard for estimating infra costs and setting pricing based on each provers setup accordingly