Dimensional constraints: DCFORM, DIMCONSTRAINT options, -PARAMETERS, value prompt, save without display overrides

DCFORM sets the annotational or dynamic form and continues into the
DIMCONSTRAINT option prompt, whose wording and last-used default match the
reference. -PARAMETERS manages parameters from the command line; a
double-clicked constraint dimension opens its value prompt. Dynamic
dimensions rescale on every camera change and their display overrides stay
out of the saved file. A driving dimension between an entity's own ends no
longer has its length retained, so a new value moves the second point along
the dimension axis; parameter edits hold the first constraint point.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

src/app/mod.rs

@@ -612,6 +612,10 @@ pub(super) struct OpenCADStudio {
     pub constraint_solve_mode: bool,
     pub constraint_infer: bool,
     pub constraint_bar_display: i16,
+    /// DCFORM: new dimensional constraints use the annotational form.
+    pub constraint_form_annotational: bool,
+    /// The dimensional constraint DIMCONSTRAINT offers by default: the last one used.
+    pub dim_constraint_last: &'static str,
     pub constraint_bar_mode: i16,
     /// Minutes between autosaves to a `.sv$` recovery file (SAVETIME command);
     /// 0 disables autosave.
@@ -3949,6 +3953,8 @@ impl OpenCADStudio {
             constraint_solve_mode: true,
             constraint_infer: false,
             constraint_bar_display: 3,
+            constraint_form_annotational: false,
+            dim_constraint_last: "Aligned",
             constraint_bar_mode: 4095,
             savetime_min: 10,
             default_bg_color: None,