engine: a typed parameter schema per command (CommandSpec::form)

Field, Kind, Dim and Collection describe a command's JSON parameters: numbers with
unit dimensions, choices, vectors, references to model items, groups, one-of
variants and rows. prefill, switch_variant and problems serve forms; json_schema
gives the same as JSON Schema. No command is described yet (form: None).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/model.rs

@@ -4,22 +4,25 @@ use serde_json::{Value, json};
 use super::{listed, name};
 use crate::{CommandKind, CommandSpec, EngineError, Result, Session};
 
-pub const INFO: CommandSpec = CommandSpec { id: "model.info", label: "Model Info", params: "{}", kind: CommandKind::Model, run: info };
+pub const INFO: CommandSpec = CommandSpec { id: "model.info", label: "Model Info", params: "{}", form: None, kind: CommandKind::Model, run: info };
 
 pub const UNITS: CommandSpec = CommandSpec {
     id: "model.units",
     label: "Unit System",
     params: r#"{"system": "m-kg-s-N-Pa|mm-t-s-N-MPa|mm-kg-ms-kN-GPa|mm-g-ms-N-MPa|in-lbf-s-psi|unspecified"} — labels the system the model's numbers are in; nothing is converted"#,
+    form: None,
     kind: CommandKind::Model,
     run: units,
 };
 
-pub const CHECK: CommandSpec = CommandSpec { id: "model.check", label: "Check Model", params: "{}", kind: CommandKind::Model, run: check };
+pub const CHECK: CommandSpec =
+    CommandSpec { id: "model.check", label: "Check Model", params: "{}", form: None, kind: CommandKind::Model, run: check };
 
 pub const SET_RESOLVE: CommandSpec = CommandSpec {
     id: "model.set.resolve",
     label: "Resolve Set",
     params: r#"{"name": "root"} — the set's nodes, elements and element faces on the current mesh (the first 100 of each); fails naming every member that is not on the mesh"#,
+    form: None,
     kind: CommandKind::Model,
     run: set_resolve,
 };