Hooks & tapleaf compute

📝 Draft. This chapter has not been reviewed yet — content may be incomplete or change.

Problem. Compute and store values mid-action — especially covenant script hashes that depend on other covenant script hashes.

🚧 This recipe is a stub. Outline of what it will cover:

• Hook blocks: on_resolved (per input) and on_pre_broadcast (per action), each running set assignments in declaration order.
• Assignment targets: instance.X and params.X.
• The tapleaf compute spec ("type": "tapleaf"): compiling a .simf to a covenant script hash, with params and depends_on.
• Circular dependencies: when two covenants each reference the other's hash, seed with 32 zero bytes and iterate to convergence.

In the meantime, HookBlock and ParamCompute in the field reference describe both, and Issuing the NFTs works a real tapleaf-compute chain end to end.