v0.9.20 - Immunefi Studio evidence updates

Aligns both MCP prompts and the agent skills with Immunefi Studio's live official tool contracts. Programme lookup no longer stands in for scope or rules. Adds chain-specific Blueprint sections and cited sources as evidence, retains Instascope snapshot and upgrade-history limitations, and documents requested Signals reads. Studio access remains optional; no automatic trials, programme unlocks or workspace writes. Setup: https://bountyoperator.com/mcp#immunefi . Full changelog: https://bountyoperator.com/changelog .