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: compile_params.X, params.X, args.X.
• The tapleaf compute spec (lang: "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.

See Spec.md §5.5 and §11 Step 3 in the meantime.