Render human details from the structured result contract

[HsiangNianian]

Parent

• [RFC-0003] Typed Program Result, Roll Trace, and Error Contract #4

What to build

Move human-readable explanations out of the stable data contract and render them from RFC-0003 typed values and trace graphs.

Frozen contract

• details is a v1 compatibility rendering, never a semantic field in schema 2.0.
• Renderers consume InstructionResult, RollNode, and TraceNode fields; they never parse an earlier display string.
• Localization changes wording only. Canonical expressions, codes, values, IDs, and provenance remain unchanged.
• Unknown future negotiated trace kinds receive a safe generic rendering instead of data loss or failure.

Acceptance criteria

• No consumer parses details to recover roll behavior.
• Python helpers, CLI, and TUI render from the same structured graph.
• English and Chinese rendering boundaries are explicit and testable.
• Kept, dropped, rerolled, exploded, counted, grouped, bound, and painted provenance is visible when requested.
• Display changes cannot change serialized result equality or output semantics.
• V1 details remains available through the compatibility adapter.

Blocked by

• Expose auditable traces for base, keep, and drop rolls #21
• Extend roll traces to explode, reroll, and count operations #27
• Map domain errors to a typed Python exception hierarchy #26