engine: costs paid by sacrificing a chosen permanent, or by discarding

[ninthworld]

Parent: #706. One of the exclusion families blocking the 104 M19 cards the catalog does not yet define.

Exclusion (crates/sage-engine/data/exclusions.json): Costs paid by sacrificing a permanent the player chooses, or by discarding — an activation cost may sacrifice its own source and remove its own counters, but a cost that requires picking another permanent or a card has no way to carry the choice.

This is the largest single M19 blocker: 13 of the 104 missing cards need it, and five of them need nothing else.

M19 cards blocked (13)

Complete once this lands — every other piece already exists:

#	Card	Cost shape
86	Blood Divination	additional cast cost: sacrifice a creature
91	Demon of Catastrophes	additional cast cost: sacrifice a creature
115	Ravenous Harpy	activation: sacrifice another creature
136	Dismissive Pyromancer	activation: discard a card
144	Goblin Trashmaster	activation: sacrifice a Goblin

Blocked here and elsewhere too:

#	Card	Cost shape	Also needs
4	Ajani's Last Stand	sacrifice this as an optional cost	optional non-mana costs; a discarded-from-hand trigger
69	Sai, Master Thopterist	activation: sacrifice two artifacts	a cast trigger filtered to artifact spells
99	Graveyard Marshal	activation: exile a chosen card from a graveyard	—
134	Dark-Dweller Oracle	activation: sacrifice a creature	playing a card from exile
163	Thud	additional cast cost: sacrifice a creature	an amount read off the sacrificed creature
201	Scapeshift	sacrifice any number of lands	a search sized by the number sacrificed
213	Brawl-Bash Ogre	optional sacrifice on an attack trigger	optional non-mana costs
214	Chromium, the Mutable	activation: discard a card	loses-all-abilities

Scope

1. Let a cost carry a choice made at announcement. Action::ActivateAbility and the cast action already carry targets: Vec<Target> in the parameterized form ADR 0004 describes; a chosen sacrifice or discard is not a target and needs its own slot on the action rather than being smuggled into that list.
2. Widen additional_cost beyond discard: a sacrifice with a permanent filter (creature, a subtype).
3. Widen Cost with the same, for activated abilities.
4. Advertise the candidates the way target_requirements advertises target slots, so the client keeps choosing from a server-computed list and computes no legality itself.
5. Costs are paid as the spell goes on the stack (CR 601.2h): an unpayable cost means the action is never offered, and the sacrifice is a real death every dies-watcher sees, exactly as sacrifice_this already is.

This is a protocol change. docs/protocol.md, sage-protocol, and the TypeScript mirror move in the same PR.

Acceptance criteria

• The five cards above are authored in crates/sage-engine/data/catalog/, printed in data/sets/M19.json, and covered by tests driving the real apply_action.
• An unpayable cost withholds the action; a paid one is paid before resolution and cannot be countered away.
• Generated rules text (crates/sage-server/src/rules_text) states the cost.
• The exclusion narrows to what still cannot be written; make compat regenerated and committed.
• docs/card-schema.md and docs/protocol.md updated. No rules logic added to the client.
• make verify green.

[ninthworld]

Split: the cast half is done, the activation half is not

PR #752 lands the additional cast cost. Leaving this issue open for the rest.

Done

#	Card	Status
86	Blood Divination	authored, printed, tested
91	Demon of Catastrophes	authored, printed, tested

AdditionalCost::Sacrifice { card_type } and CostPayment::Sacrifice(PermanentId), gated at the offer (CR 601.2b), charged after the spell is on the stack (CR 601.2h), and a real death down the leaves-battlefield seam.

No protocol change was needed. CostPayment already carried a Discard on the cast action, and Prompt::SelectFromZone takes a free-form zone, so the sacrifice poses over "battlefield" on a cost_sacrifice slot with the Rust types, the Zod mirror, and the client untouched. That is worth knowing before scoping the rest: this issue's original framing assumed a protocol change for the whole family, and half of it turned out not to need one.

Left

Action::ActivateAbility names only its source, its ability, and its targets — there is nowhere for a chosen sacrifice or discard to ride. That needs a payment list on the action, which is a protocol change (the action shape, the TypeScript mirror, and the client's submission path).

Complete once it lands:

#	Card	Cost
115	Ravenous Harpy	{1}, sacrifice another creature
136	Dismissive Pyromancer	{R}, {T}, discard a card
144	Goblin Trashmaster	sacrifice a Goblin

Still blocked here and elsewhere: 4 Ajani's Last Stand, 69 Sai (needs a cast-artifact trigger), 99 Graveyard Marshal (exiling a graveyard card as a cost — a third zone), 134 Dark-Dweller Oracle, 163 Thud, 201 Scapeshift, 213 Brawl-Bash Ogre, 214 Chromium.

The exclusion has been narrowed to name exactly what remains: Activation costs paid by sacrificing another permanent, or by discarding.

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